Miguel, you stated "Mostly I propose that people act responsibly..."
Reality is that there are many people in the world who do not act "responsibly". Some of these people actually visit DCHS. Regarding dogs attempting to come in the pools, I have had excellent success with the following statement to the dog owner - "Please do not let your dog come into the pool". 99% of the time, this is all that is needed. For the 1% that require further explanation, I simply say something like, "It's not appropriate or hygenic".