I completely agree!!! Plus, they will never watch the video again. It'll be on their phones, taking up space for no reason when it's all available on the internet and they can see their own face in the scene.
I always think this too of people at big, filmed/televised events. Even the newscasters dinner the other night. They were videoing with their phones while I was watching it on the internet. Trust me, it will be on the web forever and you won't have your face hidden by your stupid phone.