I personally would not put "hobby" gifts on a wedding registry. I have never looked at a backpacking item as a life investment. There will always be a lighter, techier, flavor-of-the-month item to come along. So in my opinion gifts such as; ropes, tents, and headlamps, do not match the occasion.
A wedding conveys life long commitment, love, long suffering, joy, sacrifice, timelessness. Dinnerware, quality tools, art, furniture, items that meet everyday life needs... are more in line with those attributes than camping gear.
That's my opinion.