It many matches I have seen and easily used a way to check if people are personoids by getting them to click "SQUARE" on a throable Syringe that is near interactive items. If they hesitate, don't do it or pick it up its an easy and cheap way to find out if they are a personoid.

Filtering through everyone at the start of the round when a Syringe like that is found is not fun to play around or with.