It's (Not) All in the Sign

The balcony of our apartment looks down on the entrance of the "coto" (gated subdivision community) next door. Beside the entry is a pretty fountain, that adds pleasant splashing to the usual shriek and rumble of traffic noise. The other day, though, I noticed that not only was it not running, but the water had been completely drained from it. I wondered idly why and figured it must have something to do with cleaning or a leak. It wasn't till this afternoon that I noticed a sign posted over the fountain.

"Si tu Perro se hace/Tu no te hagas"

As far as my woefully limited Spanish and Google translate can tell me, this says (literally), "If your dog makes, you do not play." 

I'm hoping my friends who are much more fluent than I can shed some light on this sign, because obviously there's something missing in my translation. It reminds me of street signs like this one:

I can't help but think of everything that is implied. We must assume that the dogs are doing something in the fountain. What are they doing? I have a guess, but I think I'll leave that to the imagination. And is it that while the dogs are doing this, "you" don't get to enjoy the fountain? Or is it that the fountain is not playing as long as the dogs are doing this? I just don't know.

I'd be tempted to point to this sign as an example of how Spanish is full of assumptions, but that would be a faulty, not to mention low, blow. After all, it didn't take me long to remember our American "slow children" and how that must make non-native English speakers scratch their heads. 

Language is a funny beast.