Ours was leaking a number of years ago and just found a straight fitting to replace it. Now that's not to say the RW hasn't done something stupid and added some unknown size fitting.
Yes I know it's suppose to be a safety feature, but with the new tanks if you spring a major leak they will shut off the flow. So my opinion is it's just a left over from the early days.
Michelle & Ann
2018 Chevy 3500HD Crew Cab High Country DRW, D/A, 2016 RW39MB, Dual ACs, Auto Level, Auto Sat Dish, Stack W/D, King Sleep #, 17.5" Sailuns w/Disc, MORryde IS & Pin, Comfort Ride Hitch, 5.5 Onan, Res Fridge & Induction Cook Top