> least harm while allowing maximum freedom is the true

According to who?

Is your quadcopter allowed to videotape and infringe on my right to privacy?

Is the added noise of someone having a BBQ party in the park a harm or not? What about people drinking?

> Ergo, any vehicle that can co-exist without hampering or endangering others enjoying the park is okay.

So are cop cars allowed? Cops routinely drive into parks to harass homeless people or arrest drug dealers. Are you ruining their enjoyment of the parks?