Be sure and check the numbers on the trailers you pull. We had 3 guys get a vacation over one wrong digit. No body caught it and they gave 3 days off to the yard jockey and both drivers at each end. Everyone is pointing fingers at the yard man but all we have to do is make sure everything is in check. Those yard guys hook at least 40 sets a day and they will make mistakes. Look at the numbers and check those pins. You need a light. Tractor supply has a little led light for $3 that's bright enough to shine up in there and see if the arm is locked securely. Lose a trailer you will more than likely lose your job.