My mom doesn't snoop but I wouldn't mind. I have nothing to hide and I know she'd only do it out of love and just being sure that I'm not doing anything wrong or harmful.

If/when I have kids, I'd try to give them their own space but I'd snoop if I had any weird feelings about anything. If the kid was mad at me for a while, well, they'd get over it and they'd someday realize that it was only to ensure his/her well-being.