Totally agree with all the above, record boxes should also be locked when not in use and use smaller play boxes, these are small measures to prevent a life altering experience. Having somebody on hand is the least a promoter should do when you consider the value of rare stuff 20 years ago to now. Its a different world now and the scene needs its collective shit together on this one. Peps & Kitch's experience and anyone else over the years that its happened to, this should be a warning that someone is at it and they might be ambitious. The best way to avoid risk is not expose yourself to it and to minimise it where it does exist.
Logically, all promoters should have this covered in the event risk assessment, which should be standard practice to legally cover themselves at the very least. Trust is one thing but leaving yourself wide open is another. If you take all necessary precautions it will minimise any suspicion.
Sorry mate gotta concentrate on my spot, happy to talk to you afterwards. Sorry mate venue policy, no one else on stage, Health & safety.
Altered this based on the good news below. Still think a chain will give DJs peace of mind