The law as I understand it
As I understand the law it is illegal to obtain information that isn't avaiable to all players at the table. This has always been open to a variety of interpetations.
Several (or could be many) years ago two players were arrested in LV for playing hole card. I don't remember the case or the players, but I do remember what happened. The case was thrown out of court because, even though one player saw the card value and signaled it to the other player across the table, the inability of the dealer to properly protect his hole card that allowed the one player to see it was not considered an act of cheating. The information was available, and the players used it.
To my knowledge the only cases of this type that will lead to an arrest and cheating case is when a player uses some type of device to get this information, ie., mirror, camera in the belt buckle, shinny Zippo lighter (shiner), etc. I doubt a case could be built around a wheelchair. The casino does have some responsibilty to use common sense in protecting their games. A person sitting low in a wheelchair should invoke a greater amount of care in placing the hole card on the casinos part.
Also, I don't think the State of Nevada would make a case about someone "spooking" a game from behind. Again, the same argument. The casino has to be responsible to some extent.
One more tidbit, even if the person is cheating, it doesn't warrant the casino security to lay a finger on him. Taking someone into the back room and beating the crap out of them can NEVER be allowed.
My two cents,
Zman