I am sure that there are people there with equity cards. I don't think that they all have had experence on broadway or national tours of broadway shows ect. But, it is not that hard to get an equity card these days and I am sure that there are people who have them that saw the show and thought they would try there luck.
I do think it's a bit much to call anyone who has an equity card that is on this show a mole. I highly doubt that equity would have "moles" placed in the show. Equity knows the casting rules and and so do the producers. Prior to shooting the show they had an equity call for the roles of Sandy and Danny. Then they did the show as an open cast call.
"If you try to shag my husband while I am still alive, I will shove the art of motorcycle maintenance up your rancid little Cu**. That's a good dear"
Tom Stoppard's Rock N Roll