This is one really good example I think of demonstrating the need to get something done about the whole 1000 foot thing. We have the same situation here in VA BH -- parks that are placed either on school grounds or tangent to that. One park that I'm very familiar with it is all but impossible to determine when you are on actual school grounds. Add to that there is more than one school there. Oh, and also -- the only parking that you can use is for both school and park and so according to what I've been told it is school grounds....or not...or is...or isn't. There is a ball field that the school claims is school property, and yet conflicting maps (on record with the city itself) show it to on one map to be school property and another it is not. And the elephant in the room here is that given how often encounters with a LEO involve problems (e.g., the LEO believing that it is illegal for one thing that isn't) I don't believe you're going to have the time to get the officer to look over plot lines after an urgent MWAG on school grounds.
The law is a bad one. I think that we here understand and agree with that. I'm just wondering if it could be that these mixed use parks that are being put in place (and I can't believe that VA BH and the OP's park are unique -- I have to believe that with limited land availability and budget constraints that they are popping up in many states) could become a basis for the law not working. It's one thing, I think, to have to make a claim that simply walking past a school puts you at potential risk....and another to deny a citizen the lawful right to use a city park simply because the citizen is exercising a constitutional right.