The theater is dark, and she probably didn't realize it had night vision cameras for security. Most people will also not have phones at hand, as its a rude act in a theater.

She really thought she could be an asshole because social pressure and darkness made it hard to prove she was an asshole after the fact. Its why she came out lying hard about vaping around pregnant women and somehow didn't mention have her chest gropped and grabbing for dick around a bunch of people/kids.