One: Have a Nice Month at Work, Honey!

If a crewmate is actively pursuing you and has not communicated their reason for doing so, that is not your crewmate.
If you see a crewmate actively performing sabotage on facility operation, that is not your crewmate.
If you see a crewmate pop out of a vent, that is not your crewmate.
If your crewmate doesn't do any of their tasks ever, they are not your crewmate.