Did I do the right thing?

This is the question the poster asked. I don't see that he asked if he should have got out and helped. He probably should have (hindsight's 20/20), but this isn't what he asked. Sometimes even seasoned drivers make multiple attempts backing into a dock, so you can't assume every driver needs help. Some can even get downright testy if you make that assumption, like you're insulting their driving skills. Yeah, an ounce of prevention is worth a pound of cure, but it's not always applied. Maybe the OP couldn't react in enough time, who knows? He does. We don't, we weren't there.

See, I'm one of these real weird people who think that when one is given a CDL, they should already know how to drive that truck and know how to back into a dock. It's just common sense and I'm kind of hard-nosed in that respect. And that driver, if in doubt, should have been trained to GET OUT AND LOOK, if he was having difficulty in backing. So the shame shouldn't be on the driver you're scolding but on the one who passed this driver and gave him a CDL, or the company who employs/contracts him, without knowing basic safety skills. You all seem to have your panties in a bunch at the wrong person. We would all have had to be there to know if the OP really could have prevented this from happening. Accidents happen in fractions of seconds. Everyone reacts differently to a situation where we have to react very quickly. My husband reacted one time when my son engaged the gear on a 2,000+lb vehicle. He tried to keep the car from rolling backward (he was behind the vehicle, he's strong, but he wasn't that strong lol). I saw what was happening and grabbed the door, wrenched it open and dove in head first and put my hand on the foot brake, my stepson just stood there (he froze to the spot). So everyone reacts differently to a situation.

And the OP did the right thing by letting the shipper know what happened. This way it will make the party responsible for the damages responsible for the repair costs, instead of the party who owns the trailer. It really bothers me that someone could back into a vehicle/trailer and not say anything to anyone and just take off, this speaks volumes of that person's character. Technically, isn't it considered hit and run? And if so, do we really want that kind of driver driving a 80,000lb weapon down the road next to our families?

Sorry about the rant.