I'll presume that you're a troll but you drag out the age old "If you've got nothing to hide... argument"
Here are a couple of issues with this argument.
1. Retroactive violation of new laws:
Let's imagine that you're a smoker and that you smoke in your house. The government could pass a law saying "Smoking is not allowed inside any building. Anyone caught must pay a $500 fine." They can now either go back and look at their surveillance data and retroactively charge you for smoking in your house in the past
The problem there is not the surveillance, it's the retroactive law. It's fundamentally wrong that I can do something legal today, and then tomorrow the law might change retroactively so that I can be prosecuted for doing something that was legal at the time that I did it. It's irrelevant whether the evidence is from surveillance (covert or otherwise) or from witnesses who saw me (in public or in private), or by my own admission. If I can't travel back in time to change my behaviour, nobody should be able to change the legality of my past behaviour.