Honestly, I shouldn't be surprised.
Oh...I forgot the best excuse I ever heard from a parent.
A kid who was an absolute horror plagiarised. I don't say "horror" lightly. The mother had attended the same school and - according to my older colleagues - had been a nightmare. The kid was transferred to us from another school after a violent episode there and was equally violent after coming to us.
The mother threatened to sue when we informed her that her pride and joy had been inebriated during a prelim - wandered up and down the aisles giggling and banging desks.
If I'd been in the exam hall the kid would have been out immediately. Unfortunately, the invigilators were not school staff and not as robust as we would have been.
Other kids reported that the kid had an empty quarter bottle of vodka in their bag. Of course, the bag wasn't searched.
This was the same kid where the I had to tell the heidie that - no, the kid couldn't have uploaded an essay several years earlier.
Anyway, when mummy came in and was given the evidence the excuse was: "She didn't know that it was plagiarism because she didn't copy and paste - she wrote it in her own handwriting."
NB The kid had not written anything in her own handwriting.