This requires one thing for sure:
Someone who keeps everything running during the hibernation. And that someone needs to have quite some power and must definitely be a perfectionist.
What happens to a train, if the train engineer suddenly decides to take a nap in the middle of the track? Well, most modern trains (not so modern to be honest) have measures against crashes in that case, but there definitely will be cases, where this ends ugly. Or consider a highway. Multiple crash, here we come. That one guy whos going climbing has definitely lived the longest part of his life, if the hibernation kicks in while he's on some climbing track.
Consider a nuclear power plant without engineers. That won't work out that well for all too long. Noone wants to wake up on a planet that basically became uninhabitable by hundreds of meltdowns. On the other hand for noone to notice the hibernation, the whole infrastructure needs to keep running. It'd be a bit weird, if you took a nap and woke up to a global blackout. And quite a few sorts of energy-infrastructure require regular maintenance or even fueling to be kept running. This goes from power supply lines to entire power-plants.
A few years are definitely enough time for the sentence "nature takes back what is its" to come true. Larger cities already have issues with everything from rats to bears, which are attracted by cities as synanthropes. Now wait a few years without any humans being in the way and the city will have plenty of inhabitants that weren't there beforehand. Pets, especially carnivores like cats (not that much) and dogs will definitely impose a problem. So you've somehow got to keep fauna at bay. On the other hand going to sleep and waking up with the skeleton of your beloved brutus in the living-room would be suspicious to say the least as well. This is one of the simpler problems to solve: hibernate the animals as well.
Googling for what Chernobyl looked like in 1990 should give you a vague impression of what happens to a city, if noone is there to care about it. You'll need an army of gardeners to stop this problem from getting out of hands. Especially since plants will start to dissolve streets and buildings over a few years (tree roots, etc). You might have a really nice looking city with a lot of green areas, when waking up again from hibernation, but I guess most people will notice.
One doesn't need to be astronomer to immediately notice somethings not all alright, when looking at any electronic media. Every PC has a built-in battery that keeps it's time-keeping chip alive. While that battery will die sooner or later - another problem - I'll at least notice that my PC will notify me about the fact that the battery ran out of power and the fact that the clocks a few years off. As soon as we use a bit of astronomy, we finally get to the point where this will finally get entirely undoable.
Keeping the world in a fully functional state requires resources. Be it batteries, fuel, replacements, tools, somehow all will need to be produced. Now imagine the power-plant topic: An uranium-mine that overnight gets entirely exploited will for sure look fishy to someone. Same goes for production of batteries. Basically quite a large part of the economy would have to be kept running in order to prevent people from noticing anything suspicious when they wake up. Which itself will produce noticeable results. The larger the required amount of resources, the more noticeable the results. Transportation of goods to their destination requires fuel, which run short pretty fast, if not replenished, which in turn drains an oil-field. "We're missing several bio barrels of oil" is definitely a result you won't be able to hide.
So in short:
Hiding the results is only partially possible at all. And even that "partially" requires an army of perfectionists rather than a few people that escaped hibernation. Keeping this world running requires 7bio people in it's current state - well, that's a bit of an exaggeration, but I think you get the problem - keeping it in the state it's currently in won't require much less.