In our little town, people used to be responsible and put up signs in certain areas for community events like Kiwanis BBQs, Veteran's Fundraisers, Craft Shows, FFA Horse Shows, etc.--along with your basic yard sale signs.
Everyone was respectful and didn't abuse the privilege, and signs were cleaned up when the event was over.
Then the 'I Pay Cash For Houses' 'Make Money At Home' and 'I Wrestle Alligators For Your Next Party' (OK, maybe not that one) guys showed up and so littered the town with crappy, obnoxious signage that they had to pass an ordinance outlawing signs.
They even put up a sign saying so, and there it dwelt in solitary splendor for months...
Until today:
Yup, this is how we do irony up here...whoever did this, you are our hero. The thing is even custom-crafted from wood and a lot of care went into it. We'd discussed doing exactly this as soon as the yellow sign went up, just hadn't done it yet.
Bless you, we salute you mystery smartass!