Cheerleaders are such a waste of gym space.
My suggestion is to do the best that you can in terms of teaching technique. But, at the end of the day...keep them happy and take their money. Quite honestly, that's their true purpose in the gym world...money. If it weren't for the almighty dollar, I guarantee that most gymnastics-focused facilities would not offer a cheer program.
Ouch. That was a bit harsh.
If somebody comes in and wants to learn to tumble, they're welcome to learn as far as I'm concerned, regardless of their background. As long as a kid is having fun and learning, I really don't care if they're gymnasts, martial artists, cheerleaders, skaters, or what.
If they're draging their feet, then yes, it's a waste of gym space and coach time, but this is equally true of real gymnasts who don't put forth the full effort.
That said, cheerleader tumbling is pretty ugly most of the time, and can be a real pain to fix.