Firstly, I know this is incredibly trivial, but I feel like writing a bit of a snarky note, and thought I'd get a second opinion first before I piss of the teacher.. 
DD 8 has home/class spellings to do each week, which she fills out all at once when we remember each night Mon - Thurs, followed by a class test on Fri. The list of words is in a column on the left of the page, then each day is a column across the page. The instruction is to look briefly at the word, then write it in the appropriate box. So that DD doesn't just copy them, I cut the word column off with scissors so I can read them out to her. The first time we did this I just put the two pieces back in her book bag, but the teacher told DD that we shouldn't cut up the sheet. So now every week I sellotape the sheet back together.
This week I forgot to sellotape it, and when DD handed in the two pieces of paper, the teacher said "You're not allowed to do that" and threw the spellings straight in the bin. DD tried to explain but the teacher said "You have no right to do that".
Is it really such a big deal that I've cut the word column off that she would throw DD's homework in the bin in front of her?
She can still see what the words are as they're written there four times. Is it that I am desecrating sacred school spelling sheets?
I'd have thought she'd be glad that I'm taking enough of an interest to read them out to her rather than her just copy them.
It just seems a bit mean to chuck something straight in the bin that DD's spent time and effort doing. AIBU to write her a note to that effect?