Gray Tank - towing while not empty

[MBushaw]

I did the Poor Man SeaLand and got way more intimate with the plumbing than I wanted.
I do not trust any of the plumbing to hold up to a trip down a bumpy road with fluid. And with the suspension on a trailer all roads are bumpy! This is not a TM issue but a general trailer thing for me. I would empty the freshwater lines prior to towing if I didn’t get dirty looks for making puddles at the campsite.
I know I’m a bit extreme and thousands tow every day with full tanks, but some do leak. I don’t want to be a leaker.