Her campaign team was there to know what Trump was saying when the mic was off during the last debate with Biden. I think they likely have some great insider information on top of the basic strategy. I think they know from experience, not just theory, that he just isn’t in control of himself enough to go that long without embarrassing/racist/misogynistic/whatever outbursts.
The police just see themselves not as exploited protectors of capital but rather temporarily embarrassed felons.