A belligerent passenger shouldn't be allowed to hold up an entire bus of passengers - most of whom have to make it to an appointed place at an appointed time.
The human bus driver is literally the compliance version of the AI.
Should you not complying the rules / laws in an autonomous bus, the results will probably be the same
The bus driver doesn't want to explain to his boss why his vehicle reeks of durian. The pungent smell will be in the aircon system for at least a week if he didn't turn the a/c off.