Illegal drugs, no, because they're illegal. Bombs, guns, fireworks, power tools, stove, and even a recliner, probably not, since those can pose a threat to people's safety and are either illegal or regulated already. As for stereos and, yeah, they probably should list that somewhere.
The kicker is whether or not the OP was told all this before-hand, at the time of purchase. Or at the very least pointed toward a list of prohibited items. Given that they were allowing P&S cameras, there's little reason for the OP to think that they wouldn't allow an SLR; they certainly weren't preventing photography at the concert.
Griffin, your link applies to searches conducted by officers of the law. It does not provide civilians who are not officers of the law to conduct any of the searches and seizures explained in the document. So again, it's a moot point. The people taking the gear are not police officers and don't have a right to force the OP to do so. And as I said, while they can refuse entry, they couldn't do so without offering a full refund of the ticket price, given that the OP was (I assume) not informed about their policy beforehand at the time of purchase.
There are other related questions that need to be answered, such as whether or not the purveyors of the concert were indeed the owners of the establishment at which the concert was being held, and whether or not the security guards who demanded forfeiture of the OP's gear were under said owner's employ.
The bottom line I'm trying to establish here is that security guards are not police officers, and hold none of the powers of arrest, search, and seizure that police officers do. And even so, police themselves are very much restricted in under what circumstances they may conduct a search without a warrant.
The exceptions to the 4th amendment were spelled out by the Supreme court for law enforcement and school officials. The Supreme Court has also long held a lesser standard for Citizens then they hold for law enforcement. If an LEO walks into your residence without a search warrant and conducts a search, baring one of the exceptions previously listed, any evidence found by them would not be admissible in court.
If some citizen, on their own and not at the direction of any LEO or agency did the same thing, any evidence they found and seized would be admissible. It only becomes inadmissible if they are working at the direction of Law Enforcement.
The purveyors of the event do not have to be the owners. If they have leased the venue it is no different than you renting a hotel room. That space becomes yours for the time and terms of the lease or rental. It is their space and they control it, just as you have a right to privacy with that hotel room you rented until that lease or rental expires.
The bottom line is; It was and continues to be private property and they have the right to set the rules for that space. Don't want to give up your gear, get out of line and take it back to YOUR vehicle where you do have an expectation of privacy. Laziness is not an excuse under the law.
I noticed you forgot the blowup doll and lube. What happened to her or him?:lmao: :lmao: :lmao: :lmao: :lmao: