Steam from the kettle setting off a smoke alarm seems a likely explanation for the rule. Evacuating a hall for a false alarm is a major pain* for everyone, expensive, wastes fire service time, involves the uni doing paperwork etc. So I think they (or more likely their insurers) make a blanket ban on any cooking / kitchen appliances including kettles in rooms since they are available in the kitchen, where the fire alarm system will have a heat detector rather than a smoke, to avoid false alarms.
OTOH the rule might be arbitrary and not based on any technical limitation. It may have been introduced after an accident and then introduced to pacify the insurers, or some other random reason. Yes, there is an increased possibility of tripping the S/O circuit if lots of kettles are switched on during the TV ads, but in my day watching TV, on the few occasions we had time for it, was a group activity followed by a round of teas / coffees made in the kitchen. I don't recall kettles being prohibited but we didn't have smoke detectors in the rooms.
*I have some experience of the misery of evacuating a hall from working in the SU building that was at the base of a tower block. If someone elbowed a break-glass in one of the venues during a crowded gig, we had to evacuate both SU venues (1700 capacity) and the hall too. The sleepy people in the hall were not usually best pleased.
. If anyone could help explain whether there is a genuine reason it would be highly appreciated!
