Tire Pressure Monitoring System problems of the 2004 Chevrolet Trailblazer

I am in the quick lube business and change oil on approximately 150 vehicles a day. Part of our service includes checking the tire pressure. On about 10% of the vehicles that have the "tire pressure monitoring system" we find corrosion and failing valve stems. On many instances the valve stem has broken off and because we were checking the tires we have to pay for the repair that can run into hundreds of dollars. These valve stem have been manufactured using incompatible materials that cause corrosian. It is not fair to us that we should have to pay $250 to repair a tpms valve stem due to inadaquate manufacturing. We have chosen to "not" check the tire pressure on the vehicles that upon visual inspection have corroded valve stems. This is a very dangerous condition for the consumer in that it is very important that the tire pressure is regularly checked. In my opinion a recall should be made on all vehicles with these inferior valve stems. Most american manufactured vehicles are to blame. This is a serious safety hasard that is only getting worse as time goes by.