Not in my house, but in extended family, a mom left phone on counter while exercising. Adult aged, extremely emotionally immature daughter accessed phone and read all texts and messages. Wanted to talk shit afterwards. The mom had conversations not meant for the daughter in the texts, but of course the young un was pissed about some critical comments.
Also noted, following the weekend visit, many drawers were "ajar" and not seated fully in the dressers and cabinets. There are multiple journals kept that were moved/ rummaged through.
Mom is more crushed by the destruction of her trust by the daughter, than any "secrets" that got out.
1. I wouldn't have engaged in any subsequent conversations related to the phone; but then again, I'm the dude who won't even open his wife's purse, much less go looking through her phone.
2. I'm the guy who would gripe about someone putting pliers back in the wrong drawer- things go where they go, and folks know I will notice. I would accept said behavior as a statement that they don't want a relationship any more. I would be pissed/ disappointed, but would never trust them again.