I only have an anecdote, but I had a day to kill in LA a few years back, and really fancied going to a pistol range (never tried - only used a shotgun here in the UK) - Googling and phoning all the ranges I could find within the LA area I couldn't find any that would let me go without somebody else with me (I was out there alone for work).

I have a number of friends who are huge gun fiends, who are always hounding me to go with them so they have the second person. This is just for handguns, long guns, for some reason, don't have that requirement, and allow you to go out on the range solo.