I think too much is made of event security. I run a system where the volume of events is never beyond what myself, and staff, can cope with in terms of security. Cheaters can easily be spotted as can spammers, and if a tight ship is run there are no real threats to security. Clubs try to grow too big too quickly and burn out, for little reward. This is usually why they close. As for the recent fuss over alts, they are easy to spot without the need for dodgy databases stored in some random persons basement.
Stopping object entry and the running of scripts are two basic functions that can be configured on the land, mine are set to group only, as is rez. I have a security system that is grid wide running off a server, which enables me to give out Remote HUDs to staff in the event I can't get online and gives them the option to ban people. My land is not, and never will be deeded, although it is set to a group.
There will always be obnoxious people but they are rare. The main issue appears to be contests. I have my contests configured so that only contestants can vote which stops the mass TPing of friends at the end of an event. Contestants do have to join the group now too, which I resented doing but now the group limit has been increased is less of an issue. I add casual staff to a block list in my board which prevents the awkward conversation about reminding on duty staff they are not permitted to enter the contest. My DJs take a personal interest in helping me to spot people not in theme, or any other dodgy goings on but really this sort of thing goes with the territory and is not really a security issue per se.