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.
This makes me think of airports and terrorism. I remember standing in a crowd of 1000+ people trying to get through security theater at JFK, and thinking "Anyone could just walk a giant suitcase bomb into this crowd".
That not even one follow-up attack like that—assuredly crippling air travel for months, at least, and increasing the cost of it probably permanently, aside from easily killing dozens per occurrence—happened in the months after 9/11 was when I started wondering whether this Al Qaeda thing was half as well-resourced in the US, and half as well-coordinated, as officials were saying at the time.
Sure, I think the limit is too high too. I just don't think there's going to be any exercising of these rules except against absolutely brazen cases of going over limit.
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.