My set up has an on/off lever coming right from the regulator with a barb on it that a large diameter piece of hose attach's to.
Then there's another barb that is my reducing fitting that I attach my aquarium tubing to, in the other end of the hose. I use a 'worm screw clamp' on each end of that hose to protect from leaks.
Not sure it that's what you're talking about, but if so, yes it's a good idea to clamp those large diameter hoses.
I set my outlet pressure from the regulator to the hose @ 10psi so we're not dealing with a great deal of pressure here, but it's still a good idea to clamp it.
I dip the whole thing(all fittings) into a container of water to test for leaks, once assembled to assure of no leaks.
Len