I don't think "hiding things" is right. Not mentioning unimportant details is different.
I don't mention every person I see somewhere. I don't purposely NOT mention it either. I'm not one to hide things for the sake of argument, because there is still the underlying issue.
If my SO is going to bitch about money, then we have an issue. We need to deal with that issue (money) instead of hiding things.
So I think there is a difference. Don't LIE to me or HIDE things. But I am not going to ask how many beers he had (unless he drove or something). I'm not going to care who he saw. I think hiding things to avoid an argument is childish.
I'm guilty if hiding things that would make my DH freak out. But little things that are a big deal to him, like I broke a plate while washing dishes, or LO had an accident, or some drama with our friends. Those types of things.
I don't consider it hiding anything. I do not tell my SO everytime I go for a coffee with a friend on my work break, I don't tell him if I stop into Wal-Mart for a few things, I don't tell him about every single person I meet or talk to everyday. I'm not hiding anything though, if he asked I would tell him but I can't see him caring lol.