Is it bad ju-ju to attach a wood and glass kayak to a pick-up with one end on the cab and one end attached to the box, given that the cab and box roll left and right independently of one another?

I have driven hundreds of miles on really bad logging roads with whitewater canoes attached in this manner and have had no ill effects, but I think a wood and glass boat may be another story.

Should I attach it only to the box?

Thanks, M