Crashing other people's cellphone conversations

Samantha Grossman has a Time article about irritating people, and how to fuck them up:

Have you ever been out in public and heard someone gabbing way too loudly on their cell phone? Of course you have. But Greg Benson of MediocreFilms— the same team that brought us Dancing Behind People at the Mall— has come up with a brilliant way to shame these inconsiderate conversationalists. He parks himself beside the offender and pretends to be having his own phone conversation— but then begins answering the person beside him. He calls it “cell phone crashing” and the results are pretty hilarious.
Though Benson tests out the gag at the airport, you could really give it a whirl just about anywhere. 

Rico says not that he would ever advocate such public behavior... (Not much.)