Need your advice and input

A guy did that here and lost his azz,insurance and theft and idiots, crackheads would tie up the shop and not pay even after paying for shop upfront for a day or 2, would drag into days and stole him blind and ended up tearing up cars into pieces and abandoning them leaving behind a big mess that he had to clean up and get rid of,had a lot out back for such vehicles and 8 out of 10 turned out to be stolen was a legal nightmare for him,he got educated real quik and closed it down and turned it into a tire shop only,he was a super nice guy who tried to help people and got screwed bad, and since then he is not such a nice guy, I cannot blame him, for it sounded like a good idea at the time and in theory should've been a money maker,took him a year to recover most of his losses and now he doesnt take no **** from the public and is doing well now...so I guess it depends on the area and the people you deal with, which in most cases you do not have a clue until something goes wrong then its your azz on the line and when the lawdawgs get involved you lose total control on top of your losses and legal fees defending yourself...I had almost jumped in with him in the begining as I thought it would be a great plan but was I ever wrong and so glad I didnt pull the trigger and invest my time and money for if I had I would be in jail for multible assaults and destruction of something and several people wouldnt be walking without help or missing an ear or something..hey it looked good on paper and not all of them were deadbeats just 90%....