I can't believe that the employees of a Casino can be that stupid. Surely the higher ups would know better.
So called security guards in casinos are no more than private citizens authorized to carry weapons. They are not law enforcement officers and in most cases have little or no training. They also have no more right to detain a person as you or I do. When they do detain someone, they are basically making a citizen's arrest, nothing more -- and if the person hasn't done anything wrong then they are liable for their actions.
However, it has been a long standing tradition for Las Vegas Metro to back up these thugs no matter what they do. Unfortunately, even the courts tend to go along much of the time because they are human beings in a political world and the casino industry butters the state's bread, so to speak.
It is always important for an AP at higher levels to know what to do and not to do in these situations and to have an experienced attorney at the ready for incidents like these. This gentleman appears to have acted as required to strengthen his position and to not aggravate the situation further. Although it may seem clear that they violated his rights and falsely imprisoned him, the courts will often side with the casinos anyway. It's a tough nut to crack but at least he has an experienced litigator in his corner.
The sad truth is that justice is not blind when it comes to abuses of advantage players by casino employees and there is an inherent prejudice in favor of the casinos.