Can a repo man cut chain hooked on car sitting next to your being repoed because he doesnt really know who the belongs to?

It depends on the jurisdiction in which the repossession is taking place and the specific circumstances of the situation. In some jurisdictions, a repo man may be allowed to cut a chain hooked to a car sitting next to the car being repossessed if they reasonably believe that the chain is preventing them from repossessing the car they are authorized to repossess. In other jurisdictions, a repo man may not be allowed to cut a chain under any circumstances. It is always best to consult with a local attorney or law enforcement officer to determine the specific laws and regulations governing repossessions in your jurisdiction.