That's true, Jac. I've not had such problems but have seen a 'Bus full' in London. That said, when they reduced the social distancing they increases the proportion of bus seats that could be used .... & many folks are still spooked about public transport, so you'd need to be pretty unlucky to be be refused...
Still, it's another reason to have the cab no as a back up------ I only had to use it once thru' lockdown, and that was because the damn bus had been diverted owing to a burst water main and there was nothing to tell me the 'my' bus stop was out of use. I learnt only when the taxi turned up and the driver explained the circuitous route we had to use. But, that's normal chaos, nothing to do with covid.