Used to work in the exams office of a FE college.
We had a mother in very indignant that we wouldn't change the date of her daughter's A Levels, because they were meant to be on a beach in Portugal then and would lose money for cancelling. She had assumed it would be fine because she was giving us six months' notice.
But the worst was a bone idle, entitled 18yo Y13 girl who had ordered a full remark of every single paper she had sat at the last session. It was pointed out to her that she would be liable for a large bill if the grades were upheld (from memory you didn't have to pay if the paper had been wrongly marked after all). She accepts, we go ahead.
Unsurprisingly, none of the grades changed, so we duly presented her with a bill for around £450. Her mother came in absolutely raving at us for letting her order all the remarks without her mother's authority, the department would have to absorb the cost, etc etc. It was pointed out to her that the college had a relationship with her adult daughter, not her, and that to contact her in such a situation would therefore be a data protection nightmare.
Unfortunately, although the mother paid up, it resulted in a change of policy at our end, that all copies, recounts and remarks had to be paid for in full before we would send them off. Which I think will have ended up disadvantaging the poorer (in some cases desperately poor) students who couldn't scrape together enough for a single remark in the narrow window between results and remark deadline.