If you feel like going out for a rec climb, number one strategy is don't climb where a vehicle can roll up to or within sight the tree. Take care of that and there's very low chance of being bothered.
That's why when the leaves fall off the trees I lose a bunch of go-to urban climbing locations. Except at night, you can climb practically anywhere at night.
The question most often asked when I'm climbing in parks is "Are you cutting down that tree?"
The answer, "No I'm climbing just for the fun and exercise"
The response is either total confusion (why would you want to climb a tree for fun?) or "That's really cool!" or "Where can I learn how to do that?"
I've never had a person who saw me climbing in a park call the cops.
I've been rousted twice by cops because someone reported a homeless person camping in the park. Must be the backpack. It shows you what people find threatening, homeless people.
-moss