I suspect that if it looks like a crowd close to a thousand the police will shut it down - additionally you need to count those who aren't being admitted, because everyone gathering outside of the dude with the clicker (and the dude themselves) will be in close contact as a result of the event.

The clicker is effective for fire code issues (since you want to make sure X people aren't in the building) but for disease related issues you don't want those people gathering anywhere, and now 1000+ people will have been gathering (at various times of the night) just outside the venue because of the event.