The problem is he had put the truck in reverse by mistake.
Beer was dripping from the back of the trailer. The freight had slid when he slammed on the brakes, causing it to slam into the trailer doors. At least, this is what I'm assuming. The trailer is sealed and I'm not supposed to open it. I guess I'll get to see how badly damaged it is in the morning when we unload.
While it is no doubt Joe's fault that the cargo is damaged, it's also not entirely his fault. We picked this load up as part of a split; we didn't receive it at the shipper or had anything to do with the securement of it. It'll be interesting to see if it was secured at all. I know from beer loads I've loaded before that typically straps are placed in a crossed fashion. In addition to the broken beer bottles, I may discover some mangled straps as well.