Folks, you totally miss the point as to where and when we will use it. Obviously we look and follow posted heights. On main roads we have no concern. And if the road is ok to be travelling at normal speeds, no problem. But with a B we often find ourselves in small towns and country roads going slowly, often with no clearance posted, We faced just such a situation last year in rural Wisconsin. We held our breath and made it. We boondock on private property with the boondockers welcome website and sometimes are offered spots that are tight.
As I said in the original post, we will likely never use it, but if we ever do need it we will be happy we have it.
If we did hit something in that situation we would be a real inconvenience to traffic any traffic behind us I assure you.
BTW, we did FT in a large class A for three years and did fine, but we did not go in the tight places we now go in our B.