I've shown the stills round a few people.
When I show the 'stretched' stills, no one has noticed.
When I show the comparisons, hardly anyone noticed (and the person who did notice didn't think it was really noticeable unless you were looking for it).
When I pointed out that one was the right shape and the other had been made either too fat or too thin, very few could say which was which (whether the BD was stretched or the other copy made thin).
Before anyone jumps on my back, I believe every BD should be perfect, without any DNR or EE, and certainly in OAR with the correct proportions.
I just think we need to keep the level of the problem in a little perspective.