I do like the idea of using this style of vacuum breaker as opposed to the one that's in the unit.
However, wouldn't it make sense to put this on the end of the hose that attaches to the water supply side? That way, there is never any water that is spilled in the convenience center. And, if there was a sudden backflow condition, the breaker would pop, and no water should be pulled into the water supply. Maybe I don't understand the "fix" that was outlined in this post, and that's entirely possible.
ON EDIT: Actually, a fair number of the campsites that we've stayed at have these type of vacuum breakers on the water spigots already, and they are kind of a nuisance because they spew water all over you when you turn the faucet off. If I was to put one of these in the convenience center, I don't want that thing spewing water every time that I turn the hose off.
The one reason for leaving it in there is when you sell. I would be the prudent thing to make sure that the unit is to code when you sell it. If you kept the valve, you could always put it back together when you sold it.
As for just dumping (no pun intended) the power flush sprayer system all together, it does seem like something that
should work fairly well, and at this point, I'm not game to disable the whole thing just quite yet...