Sounds to me the easiest way to test is to have 3 people join a party, vote kick the dps friend for harassment, and see if the 30 min penalty is applied vs kicking them for the other reasons.

just explain to the 2nd random dps whats happening an hopefully they'll comply

Side note : needs to be an option to kick people that are going against the group or intentionally sabotaging the group because they want to be kicked.