The pesky apostrophe

AH, the pesky apostrophe.
When I wrote the post about Manny's offer of coffee, I suddenly had  doubts about the name of the coffee;
would it be "Tasters Choice", as-- many tasters choose this-- or, as turned out to be the right one "Taster's Choice" --the choice of one taster.
This came after I had espied a card on the street waiting for my bus at the bottom of the hill.
The card read :

GAY'S MEN'S ONLY
OPEN MODEL

I don't really know what the card refers to but a name of a hotel appears and a bunch of telephone numbers,.
What I do know is that whoever had the card printed had some funny ideas about apostrophes and that it made me do some checking so that I would not be caught misusing this pesky little comma looking thing.