I think my wife’s I-phone listens to us talking. Once when we were walking we discussed that it might be nice to have some wine. She was carrying her phone. We drink wine about 3 times per year. When I got home and started reading on my tablet I noticed I was being pushed wine advertisements on web sites I visited.
If she leaves Siri enabled she should expect that kind of stuff. That’s what it is - a listening and speech recognition program.