There's an app for that.

I'm at ARISIA. Volunteering in the staff lounge. We got the TV turned on to the internal channel that is a live feed from the Masquerade down in the ballroom. The audience is filing in, and we see someone's daughter pacing back and forth on the television. Mom pulls out her phone and text messages her daughter something snarky and momish. We see the girl on TV stop, pull out her phone, read the message, and start looking around for her mom.
This brings forth general laughter up in the staff lounge. Mom sends another text. I see you. Daughter reads this, and looks around more for mom. Mom and friends upstairs find this amusing. Daughter sends a text back. How can you see me. Mom sends back. Mom knows everything.
Daughter looks around and around, and still can't see mom, since TV camera doesn't work in reverse. Parental torments via I-phone. There's and app for that.