well the problem its they CAN say he stole it. I had some stuff stolen one time, found it sitting behind some douche bags house. The officer said the dude with my stuff could have me arrested if i took it back without a police report saying it was mine. I had the police report but it wasn't in the computer yet... so i had to wait there for HOURS before i could get my shit. FUCK THE SYSTEM!!!
On a side not i thing registering trailers is the most retarted thing ever. If a cop sees one that is not safe then take it but otherwise GTFO