Yes it was a bit of an assumption on my part. If it was a small or independent store I'd take the opposite view.
I believe that is called Reductio ad absurdum, and it doesn't make my point any less valid.
Sending kids down mines to find gold/jewels is a bit shitty. Getting a few hundred quid off a multimillion pound company who'd screw you over in a second if they had the opportunity isn't.