Very good point. But players should also know that a given machine can be released in multiple payout levels. You can have a row of identical games but the game in the middle could be set at 95% and the others around it set to 87%. And the casino doesn't have to identify which is which. Sometimes you can glean this from the payout tables, you can almost always glean it from video poker games.
There's a voodoo science around how casinos are laid out and how games are arranged to maximize cashflow. You can get a degree in this at UNLV.
I don't know about the US - but here in the UK all machines are required to clearly display the return to player value in the terms of the gambling license.
Yeah, sorry about the US-centric answer. Having payouts labelled is a very nice thing. Obviously Las Vegas was built on the players not knowing or understanding their long-term odds.
There's a voodoo science around how casinos are laid out and how games are arranged to maximize cashflow. You can get a degree in this at UNLV.