Customer kept following me and my assistant around yesterday on the job, offering unsolicited help and helping on certain times. I told her / him about our company and insurance safety policy and that customers can only watch from a distance, cannot help or touch our equipment. My assistant had just finished scrubbing the dinning room carpet with a 17" 175 and then left for outside to get some spotters. I was vacuuming the upstairs and decided to check on things downstairs. Just walked in time to see the customer being thrown into the kitchen.......yuck. She / he was trying to operate the 175 with the attached nylon brush on an area the customer thought my assistant skipped. I have notified my insurance company and attorney just to be safe. Today, we checked on customer, pain in one arm and a bruise on the knee. Customer admits fault in trying to operate out machinery, despite warnings. We also gave a restaurant gift card for $40 and some carpet spotters as a get well soon goodwill from our company.