Full hook-up vs fill & dump

I say make the dealer fill the fresh,gray and black tank full with clean water before you leave the dealership and go through the pumping and dumping process there. A lot of times leaks don't present themselves unless the tanks are full and if, during the emptying process, there is a leak the problem is easier to deal with if you have clean water in the tanks and not the nasty stuff and you're still at the dealership. Imagine the hassles and wasted time you'd have to go through if you were down the road and a problem presented itself. You may not be able to use the rv until you got back home and contacted your local rv repair who has to contact the selling dealer for authorization and on, and on. Actually, make them show you all systems work before leaving their property. I speak from experience!