Maybe no cost to the casino but there is a "cost" to higher level players if an express line can be used by the large number of lowest tier gamblers. Pearl at MGM requires around half the play it takes to reach the lowest tier at CET. Last time I was at MGM the few times I saw an express line somewhere the sign didn't include Pearl but I wasn't paying close attention. Never really dealt with any lines anyway. But I know I wouldn't feel too "rewarded" for being Platinum if I was in an express line and stuck behind a bunch of Pearl players just as a Noir player wouldn't feel too "rewarded" if he had to wait behind all the Platinum, Gold, and Pearls. Funny thing is that CET which tends to be worse for premium players actually offers more "premium" service to its higher tiers than Mlife. Out here in AC there are usually two separate express lines for Diamond and Seven Stars so at least Seven Stars really do get priority service. Usually nothing for Platinum though I may just have never noticed. At Mlife they basically say you can be a minnow or a high roller and priority service is the same....at least as far as the line pass tier benefit goes. Dollars to doughnuts they will change this as more and more people become aware of the express lines and start using them.