You are absolutely right of course. If ever there was a useful selling point for UKAPU or similar, this would be it. For a very low outlay, they could take out a licence, and then advertise the ability for their members to use the frequencies assigned to them....
Albeit, I confess to never having heard of anyone successfully prosecuted for using a Baofeng on PMR446 frequencies - that's not to say that it hasn't happened.