i worked at sears auto center for 2 years. the machine they had was a good machine. they have safe guards that can be used to prevent scratching. most of the clamping tire machines ive seen can do both front mount and rear mount. the tool used to take the tire off is basically a flat bar that is forced in between the tire and rim and then it's pried over the lip. the pivot point on the rim is where a arm swings into place to protect it. the foot on that arm is made out of plastic where it touches the rim. when the machine starts to spin the rim to get the tire off that metal pry bar slides off the plastic foot striking the rim. ive done that many times and it does do damage. after a few months of getting yelled at for messing rims up i figured out to pull the pry bar out before the rim started to turn, preventing the rim strike. the machines also come with at least 2 different plastic pieces to slide over the bar to prevent that as well. whether or not the tech used them? probably not. i got tired of getting yelled at so i started figuring out the right way to do things. i became very good at it. after 3-4 months i was no longer scratching rims. the plastic foot can also wear out and end up scratching the rim no matter what you do. there is also a screw on the clamp machines to keep that arm from swinging to close to the rim. the fact that your rim was painted has nothing to do with anything. there is another type of machine that sears likes to use as well. its a center post machine. it will work with alloy rims but is was designed for steel rims. instead of spinning the rim, the machine spins the pry bar that is wedged in between the rim and the tire. this will absolutely do the damage your describing. those machines are not meant to be used on any rims but steel rims. i only know that because I've done it with the outcome that you have right now. when they get busy they do what they can to get the job done. most of the time they don't have very intelligent people working there doing tires either. its a minimum wage job. at least it was when i was there. they messed up your rims because they didn't use the machine right or because they used the wrong machine. if you got to the main store (which also happened to me while i worked there) and speak to the Sears manager, should be in charge of both auto and non- auto, you can get your rims replaced. i messed up a lady's rim and i was upfront about and she flipped. went to my manager and they wouldn't do anything. so she went to everyone's manager and 2 days later the dealership dropped off a new rim. they have procedures, tools and training to do the job right and not damage your property. hope this helps a little.