Trespass and intentional infliction of emotional distress could be two issues the shopkeepers may raise in their hypothetical countersuit. A person may have rights to the goods for sale, but not be the one who pays the overhead of the business, rent and so forth.
Any claim that one litigant would make could be offset by a counterclaim, so any outcome could conceivably result in a division of damages between the two parties. It's important to be polite about such matters to encourage goodwill from adversaries, just in case either one needs to make amends. Do not assume that you know in advance how a case will conclude; the scales can tip either way. Bootlegged items might not be the only property-related rights at issue.
If a person is polite and reasonably cooperative considering the circumstances, he/she appears to be within their rights, which could help a defense against a counterclaim. If the shopkeeper were to have a heart attack because a shopper were unnecessarily cruel in communicating his/her demands, a wrongful death counterclaim would be another hypothetical to consider. So, always be nice.