The reality of it is if you're sitting in a wheelchair, short of you doing something like jumping up, sprinting to the bathroom and back, the casino is going to be too scared to **** with you.
Even if they're pretty certain you're fraudulently using the chair, if they're wrong, lifting a handicapped person out of a wheelchair and roughing them up will probably get the place shut down, and some people will be seeing jail time for it.
Even if you were there without a chair a month ago, you could have a new medical condition, and you don't have to be unable to walk to use a wheelchair. Someone may have difficulty standing/walking for long periods of time and a wheelchair could improve their quality of life.
If you do elect to pull a ploy like this, don't ever get out of your chair when you're even near casino property. If some idiot gets outta their chair and gets up outta it to lift it up into their van in the parking lot then that'll get them arrested.