We have been having this debate at work for years now (work for a sign manufacturer). I understand that on a sign that says MEN'S LOCKERS, the apostrophe goes after the N due to it's already a plural and shows possession. But is the apostrophe necessary since there are no other grammatical elements? It has to be all caps for accessibility compliance, no verbs, prepositions or even a dangling participle. So we only follow the one rule of the apostrophe. Maybe this is more of a question for the sign industry to answer, but I wanted to check in here first. Thanks