I'm working with dealerships in Missouri and I haven't heard of anyone experiencing high repos. Are they coming back shortly after purchase (month or so) or several months after? If the dealership has never experienced this before its likely due to economy. But you're probably hearing that a lot. Sorry I couldn't be more help.
Are these customers delinquent when they bring the car back? There isn't much you can do if they surprise you. They have made up thier mind to do without your rig. If you are having trouble with them paying and you are communicating with them you should help them with some type of arrangment to keep them driving on a lower payment for a period of time. I always ask, do you want to keep the car? Do you see any light at the end of the tunnel? If they do not see a solution coming soon you have to take it.
If they want to keep it and think they'll be allright in 2-3 months then I would help them.