This concept is intriguing.
I have a potential answer, but it depends on a lot of assumptions that are not clarified in the question, and they are too extensive to handle in the comments.
First, I am assuming that there is a philosophical difference between the mind and the body. That is, the mind exists independent of, but reliant upon, the existence of the body.
"Life', or the physical body part, is like a virtual reality game that the 'mind' part is playing, only every human is collectively part of the game. Just like a game, a 'save point' can be set, and the game continues, but if things do not go as expected, the player can reload the game as 'frozen' by the save point, and continue on. The player's mind, of course, remembers everything that happened the first time around, and can use that information to make modifications in her play so that this time around things will go differently. Except that, since it is a multi[player game, no one player can decide to go back to the save point. This option happens randomly, and beyond any player control.
Another difference is, the player's mind and the body are intricately linked, so the mind has no other body, and the body has no other mind (the game avatar is, in fact, part and parcel of the mind).
Another consideration is that the save point is always 24 hours (sort of like one 'turn'). You can not go back 48 hours, or 72 hours, or one week. Whatever happened up until 24 hours ago is unchangeable. It can not be redone. If you were falling off a cliff at the save point, you are falling at the same rate when the game is reset.
Another assumption - that the society has ALWAYS been this way, since 'creation', whatever form that takes.
Also, that everything physical gets reset - all of the laws of physics and all of the equations of physics, chemistry, and cosmology go back to exactly the same numbers, values, coordinates, states, that they were at reset. The physical body world is reset, but not the ephemeral mind part of the mind-body duality. The mind retains all of the experiences, memories, skills, wisdom. and knowledge gained.
If my analogy and assumptions are correct, if this is your world, read on. If not, I suppose this answer can be deleted.
In this scenario, a mistake that a person makes is not always final. If they mess up, there is a chance to re-play part of their life - one complete day's worth. But they can not depend on this. They can not plan on it happening. If they mess up, and the game gets reset to the last save, bonus for them. A second chance. If the game does not get reset, they are stuck with their decisions.
So if, for a crude example, one is married and decides to go on a hall pass, and has absolutely great mind-blowing sex with a stranger, but ends up with a communicable disease, if the day is reset they have the absolutely exquisite memory but not the consequences - they no longer have the disease. But they can not COUNT on the day being reset.
This happens even if something GOOD happens. That is, if they win a lottery and are set for life financially, and the day is reset, they can lose the lottery the next time around. Random chance is random, even between iterations.
The legal system by necessity would have to have as its basic tenet 'most recent most legal'. That is, the only thing that would be considered is the state of the world at the end of the latest iteration. Just like the end of a virtual reality game depends on the most current iteration, not on what happened in the iteration before the reset. You win or lose the game AT THE END, not in the middle. Some players that were winning, end up losing; some who were losing end up winning; but the only thing that matters is how the game ends.
There is no such thing as fair or unfair in life - things happen. Upsets happen. It gives, and it takes away. The only thing that really counts is how it is played out until the end, and the memories, skills, wisdom, knowledge, isight you gain along the way.
Looked at from another angle, our legal system is based entirely on causality. We did something that caused something else to happen. Everything is sequential.
Consider the following argument in a court of law:
"You woke up this morning and you visited your ex-spouse, you got in an argument with her, and you killed her. You had great remorse for what you did. So when you got up this morning, you remembered the consequences of you going to see your ex-wife later in the day, and you decided not to visit her. So you did not kill her. So when you woke up this morning, the consequences of your actions later on in the day caused you to do something different in the past, so your wife is not dead."
Where is the chain of causality? The act of killing her lead to you not doing something that lead to you not killing her.
The only arguably legally pertinent 'causality' chain is the most recent one. You did not kill her, therefore you are not responsible for nor did you cause her death.