Might depend on where you're camping, but I was leaving my Grays open during the winter in Florida and I ended up with a good size Cockroach living in my washer until I finally was quicker than him. So I have to assume he came in via the Gray line and then had no way to get out of the washer other than the soap/rinse compartment as he would be there when I opened to add soap.
Now all my tanks remain closed except when draining.
That's my Story and I'm sticking to it!!
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