I am a very strong hiker and marathon runner but because of a shoulder injury a pack causes me to much pain in that area. So I gave up overnight trips and just would go for runs so as not to have to care anything on my back.
I have had the pleasure of using a devise to carry my load that uses a single 16" wheel It works with a pack or bike pannier attached just above the wheel. It then extents up with a handle adjusted for you on a pole and one on the very top. There is a bungee attached down by the bags that goes to your waste, this keeps it from running away from you. It is pushed out in front of you which enables you to avoid many trail obstacles. You do have to lift it over some depending on the trail.
Here is what I am getting at I have been told that I can't use it in Wilderness Areas and even have been question about its use in National Parks. Why is this? It causes no trial damage and does not interfere with other hikers use of the trail.
Now to avoid allot of needless discussion I do understand that Mt. Bikes could cause trail damage (horse don't apparently but lets not go there ether). Mt bike could cause user conflict such as being ridden to fast down the trail. Game carts and wheel barrels could block and cause passing problem for other hikers. So with those things understood lets just discuss why a wheel used in a trail friendly manner is forbidden.