There are occasions when at booking/boarding an exception may be made to deny a PRM boarding. The examples you give Rainboe are exactly in that category.
Reading the legislation, the airline/carrier are quite within their rights to require a carer to accompany the PRM, this would then address the situations you highlight.
Of course delays may be incurred if each situation is not managed carefully, most however are just the run of the mill evryday cases that we deal with most days.
