Does the iPhone Bluetooth Blab?

I was talking to my daughter this morning and she brought up a troubling subject. She stated that she was puzzled by something that her iPhone Bluetooth app may be doing. Recently she was talking with her roommates about a subject, overweight males, and a little bit later she starting receiving ads in her favorite apps for swim suits (a product named Chubbies?). She had her iPhone Bluetooth adapter on as she uses it to send music to her Bluetooth speakers.

Same thing happened when she was talking about switching her cell phone provider, she started getting ads about different cell phone service plans. Then one of her roommates got ads about Brooklyn hair salons ... this a few hours after  she was talking about looking for a different salon, in Brooklyn. They both use ATT cellular service on their iPhones.

My daughter used AirDrop to send images, etc., to her work phone or her computer. She kept it on all the time. Once she stopped the Bluetooth adapter until she needed it, the ads stopped. Coinky-dink?

Does any one have any information on this?
Are cellular service companies doing something illegal or is this part of the tiny, tiny script that you don't read in your service agreement?

This is why I refuse to have an Amazon Echo or anything like it in the house. It is just another way for someone to listen in on your life.