to be fair most of the time all the cops want is to avoid a major incident or other people to be disrupted by a party. Even in my area they used to be sound until people really took the piss.

As for bouncers, there isn’t enough work in rave events to keep them going so many work as normal door staff on townie clubs or rentaguards elsewhere and don’t want to lose their SIA cards if they have them (or be busted for not having them at all which is an offence!) its the same has when on the roads and a police car appears and everyone suddenly slows down to just below the speed limit. Perhaps if/when the security look like they are “doing their job”, the feds aren’t going to start checking folks SIA status and/or even their immigration papers!

Getting a SIA card actually involves a fair bit of investment in time and money and wouldn’t be worth risking for a illegal rave but I expect it would be easy enough for a security operative to say to a copper “I don’t normally check the licensing arrangements, are we supposed to do that?”