Last time I saw a travel trailer do that, it was in pieces all over the place. Looked like a flat bed with a toilet mounted on it, with debris everywhere. I couldn't only tell it was a travel trailer by the toilet and the type of debris.
That one looks like a pretty tame "flop" compared to it...
I would expect that if they had seatbelts on, they walked away with only bruises.
2016 Jayco Eagle HT 29.5BHDS (ordered 12/30/15, delivered 3/8/16)
2015 F-350 crew cab, short bed, 6.7L PSD, Pullrite Superglide 3300 hitch