tis is another reason I like vans, the bikes can't fall out
well they could but you'd need to be barrel rolling down a mountainside or something dumb like leaving the door open 
A bike not tied down properly in a van can fall over and damage both the bike and the van

. May not fall far, may not fall out but it can fall over.
As the old saying goes; a fool and his motorcycle are soon parted

.
I like the new tie downs. A bit ex'y

. But to tie down and immobilise the wheel is the way to go - more stable, more reliable (no bounce, no undoing) and not stressing the suspension components.
Still have the age old problem of tie down straps - they get tangled in storage and are a shit fight to get out and use. At least these have halved the prob

.
I have thought of the same solution some time ago but I was thinking of turnbuckles to apply the tension. DIY could be done with turnbuckles a lot cheaper than the racket.
When I build me dream trailer for all my dream bikes

I might get around to DIY turnbuckle tie downs, with tyre wells

.