Of course that there will be ways to cheat the system. And you, as the author will show how, in that utopic society, crime still manage to happen unp.
The most similar story I can think of right now is The Minority Report, while also having images of crimes… it is not infallible.
I would remove the Big Leader exception (although there may be rumors of certain rich guys not getting/removing those implants), it'd be more interesting to have it posed as a democracy.
Then there are a number of ways you could have the system not effectively determine the criminal.
For example, you might have a number of people in the tube. Light goes out, it stops, when light comes back, you discover that one of the passengers was killed. Surely it must have been someone that was traveling there, but there would be no recording of the murder. (Hint: the assassin is probably the guy who was previously wearing the jacket which is now covered in blood)
In fact, in this society, where people know that everything you see is recorded, I would expect that in your society most people would prefer having sex in the dark. Theoretically, the records would only be opened if mandated by a judicial order but you never know which young functionaries could access them
Then there are the requirements for bandwidth and storage. The vendor of the chip will sell the implants at an high price and, in exchange, must support it, not only in case of malfunctioning during the whole life but also provide the storage (in fact, there are a few big brands, which then subcontract the manufacturing of the implants, and separately the storing of the recordings).
The chips are continuously transmitting the footage, they can only store a few minutes of video, just enough if you walk through a zone with bad coverage. This makes some people to take measures in an attempt to block the signal, from literally wearing tinfoil hats, to more ‘advanced’ helmets.
However, sometimes the infrastructure is unable to provide support for all video that is getting uploaded. This happens eg. on some big concerts, where there is so much people attending that it would be impossible to reconstruct the show from their implants (most packets would be lost, you would need to reconstruct it from many different people viewpoints). As such, an event like that is ideal for things which should leave no trace (you probably don't want to kill someone there, but would perfect for passing an envelope with instructions/money).
In fact, in everyday life, it is normal that portions of people sightings gets lost. By some accounts, that goes up to 20%. There is little incentive for ensuring everything is received properly and, after all, nobody notices. If the packets sent by your implant get discarded, they are not stored.
A fact that few people know is the infrastructure used for that is shared with the ubiquitous internet all citizens enjoy. And if the net is collapsed, —albeit supposedly discarded packets are chosen at random— in practice implants have lower priority and are the first to be discarded. Customers would quickly complain if their NetFlix experience didn't reach the full Mega-ultra-high definition they are paying for, but there are no such complaints for implants data.
As such, if you got a number of people heavily using the (perhaps not-too-good) network in the zone where you will be committing your crime, you would be more likely to get away with it.
Plus, you need to take into account that these devices are susceptible to failures. Some fail because people did things intending to brick it, while others are spontaneous failures that appear with the aging of the chip. Modern chips are much better and don't present these issues (or so are we told), but there are thousands of (old) people with those (old) chips. And the same reasons that makes extremely hard to remove the implant makes equally hard to replace a defective implant.
There are stories of people that, unknown to them, their implant stopped working 20 years ago.
Another thing to take into account is that, for privacy reasons, implant recordings are only kept for 90 days (unless there is an open proceeding for which it is needed). Nobody really likes their past being there, and it is really a storage problem. 90 days should be enough for everyone, right? And then you find that someone, months ago, put into the water tank of certain house a biodegradable case containing a poison.
Or that certain instructions were given long beforehand so that the patron cannot be linked. The instructions may even consist on the lack of certain action. Get to prove that!
Another interesting point is that there are rules concerning when and what can the viewed from your sightings. This may range from requiring a court order to having a reason to suspect you may have seen something at a certain time. In other words, there is a given process by which those records can be accessed. On the most common case, when you saw something interesting as a witness, you would be asked permission for accessing what you saw from 2018-12-06 12:03 to 12:15, you would agree and they could proceed quite easily. You would have right to be assisted by a lawyer, there could often be disagreements when police request records more broad than justified by what they state, etc. Quite similar to current laws regarding warrants for searching/inspecting homes or devices.
This also means that it would be possible to get off with a crime (concerning this system) if you managed not to be identified as someone to inquiry for the time needed for the records to elapse.
Interestingly, those that did most for protecting access to the sight records were not the mafias, not the small privacy-aware citizen groups, but the big corporations, that were very wary of third-parties viewing the activities of their employees.
Slanders say that these records aren't a big issue for mafia gangs, since they have insiders that can redact for them what some people recorded.
Finally, it should be taken into account that even with faithful records, there may be all kinds of differences between what can be seen and determining what happened. From someone making the other part angry (orally, not in the footage) in order to later claim it was self-defense, to innocent actions that could be interpreted in a malicious way post-facto. Surely, there would be a new profession of those that are experts in interpreting what does it mean that someone looked in a certain way (a mixture of psychology and graphoanalysis).