Right, just keep hitting them at random, and see which ones disappear the fastest. But you'd need to crowd-source it, and build an app so people could quickly geo-tag as they apply them.

I can't imagine that putting stickers on utility poles is illegal ;)

It probably actually is illegal under something like "defacing public (maybe private?) property" and just not enforced.

But might be for something like this

Right. I used to put up posters for stuff, and people did say that it was illegal to put them on utility poles. But everyone did.