Yeah, the walls aren't that tough in an RV, so mine get tied down tight in the toyhauler.
A guy at a Harley dealer where I was picking up a new bike told me they just had a customer load a brand new bike in an enclosed trailer and he wrecked and flipped the trailer on the way home. He had it strapped in well, and other than leaking fluid when upside down, the bike was spotless...
I know a guy in that didn't strap down his honda 250.... Once they hit around 70 mph the air caught the fenders and........ Yard sale.... The bike was totaled.
I always strap down. You never know when you have to stop or turn quick. It only takes a minute or two to do it right!
We had a local incident involving some equipment that wasn't tied down properly on the back of a trailer. It fell off, and someone hit it and got killed. The driver of the equipment got charged with manslaughter... Your life could change a lot not only with knowing you killed someone, but also how your life would change being in prison. It's not worth not taking the few minutes to strap down your load properly...
My neighbors used to put their ATV in the back of the truck, set the parking brake and took off. Well it worked fine for a few years, but one time they wer driving out a bumpy road, and it somehow released the parking break. My neighbor is a bad and fast driver and he kept going until the quad came through the back glass. It broke the rear glass, dented up the front and back of the truck bed, and bent the cab a little.