I was mortified today to discover that after trying on 3 tops, I'd left a makeup stain on the neck of one. This must have been where the top rubbed against my face as I took it off.) I didn't like it once on and it was also too big for me. Otherwise I would probably have felt obliged to buy it.
I just left it in the changing room with the other 2 tops I didn't buy (although I did buy one which salvaged my conscience a bit, as at least I didn't just try on, muck up, then leave). 
Should I have apologised to the staff? I was worried they might insist I buy it.
Are shops insured for this sort of thing? (I.e. Do they allow for "writing off" a certain amount of damaged / soiled goods?) This was a big chain who aren't exactly cheap, if that makes any difference...
WWYD?