I'm no engineer, but I have stayed at a Holiday Inn (before we got our TC), but I agree with Jefe 4x4 in that centering guides may have helped prevent this.
Another thought to ponder is, would a DRW truck have helped keep the unit from tipping past the point of no return vs. the SRW the OP had? IMHO, it would have put the rotation point farther out and may have kept the truck from leaning over that last little bit to allow the camper enough lean over stressing that tie down mount to the failure point and fall out.
I'm in agreement that the OP (Nolan) was caught up in the perfect storm, literally. When teaching classroom for motorcycle training, we discuss accidents as having many links in a chain and if any link is broken (a contributing factor removed), the crash (accident) doesn't occur. In his case, it appears that Nolan was in the wrong place at the right time for all these things to come together to create this situation. Thankfully no one was hurt, which is the bottom line.