Where I live that is a legal defense - it was not properly marked. Also where I live it is only considered a trespassing charge. And that is if they notice it and they ask you to leave and you don’t.
The big one for me is the schools. So far I have remained legal and not carried going to my kid’s schools.
My current house is within 400 feet of a public gradeschool so I don’t give a ratsass about that stupidass law.