1. Customer has the right to not buy. She/he can always walk out of the shop. Kudos to the salesperson on his/her persuasive skills, though.
2. One to one exchanges, and warranties, are only valid for manufacturer faults and defects. In this case, the instrument left the shop without damage and was damaged during the transit home, nothing to do with the shop or manufacturer. Too bad the guy didn't take care of it. I mean, COME ON. What do you have to do to a guitar to damage it so significantly while going home.
Sure, Gibson Les Pauls and SGs have the tendency to decapitate themselves, due to shocks. But how much of a shock do you need to subject one to actually to do that? Unless, the customer is stupid enough to have brought to a black metal mosh pit. Oh, didn't come with a hardcase? You've been had. Boo hoo for not doing your research. And I've carried my Strat in the crappy unpadded Fender gig bag so many times and it gets home unscathed, even through rush hour traffic.
tl;dr, none of these are the fault of the shop's. It was all in the customer's hands.
And cramp shops? I'm 1.78m and weigh at over 0.1 tons. I have no issues about walking in all the shops, even at the Marshall distributor on a busy day. And the way I see it, that's how some shops keep the overall costs down and need not pass on any additional burden to the customer.