I would wish to use whatever inconsequential reputation I may have to recommend to those with limited casino gambling experience that your best assurance of the honesty of a machine is the established status and reputation of the machine's manufacturer. It isn't outside the realm of possibility that a casino operator might be motivated to try to cheat or outright steal from patrons. This is a greater risk with a small, independently owned casino. In particular, there have been cases of this with some tribal casinos in some of the more remote parts of the country. But the method of cheating patrons hasn't been the use of gaffed machines.
The State of Nevada has the nation's best vetting process for the introduction of new machines into licensed casinos. If a make and model of machine has received approval for use in Nevada, that is quite good assurance that the machine is honest, and that it accurately replicates the card game or other game that it simulates, including the randomness of the draw. The same machine and game outside Nevada will operate in the same fashion as inside Nevada. So if you seen an IGT machine somewhere in the Midwest, it will operate like an IGT machine in Nevada. Creating replacement chips to insert in a machine manufactured by someone else, in order to gaffe a game, is a very difficult task. It is not going to happen. The manufacturers, such as IGT, will be very much on the lookout for any improper functioning of machines installed in their customers' casinos. If they find out about anything like that, they will not let it go on. That extends, too, to flaws in the programming that can lead to overpayment, as has come to light on at least a couple of occasions.
These comments are not meant to address the subject of deliberately designed, state-approved, non-random games, that are found in some "non-Type III" casinos, such as the New York racinos. These are typically so-called "bingo" machines that only look like regular video poker machines but that have results not affected by the player's skill. There will be some possibly-inconspicuous feature of the display that identifies the machine as a "bingo" machine.
Unfortunately, like any other, this forum attracts its share of crackpots. Anyone reading needs to be on guard and to be ready to ignore bad information that shows up here.