Bob, are you under the impression that just because you arrived and someone was playing the machine they are just going to give it up so you can play ? Every year there is somebody who complains about the same thing. All those other people playing the strike machines made the trip to the convention and more than likely waited in a line to play the machine also. Since many casinos had a red cap chaser strike mixed in with the other strikes it can take sometime to play through a machine to win the red cap strike, also if you had attended the trade sessions you more than likely could have traded for the strikes you wanted.
Until a casino tells me I can only play a machine for a certain amount of time I wouldn't stop playing a machine just because somebody else figured they had the god given right to play it as soon as they showed up.
Walt