Scoff and chuckle all you want.
This is a 2020 power move.
Any other year, when sanity is still an actual thing, then this is a psycho move.
But in 2020, there are no rules. Anything goes.
So, well-played good sir or mam down there in Pilsen for letting your neighbors know not to fuck around. (I did a little detective work, zoomed in on pic, ran a trace on/googled the school address. nbd.)
(Sidebar - I realize people from outside Chicago might be like what the fuck are you talking about?
This is a totally normal and acceptable thing in this city whenever it snows. 1/8th of an inch or 18 inches. If it snows, you can clear a spot, any spot, and claim it with your property. Usually a chair, but it can be anything.)
Cool story Hansel.