As Reggio said...I do believe that you need permission to post something on city property...I mean we are not even allowed to put things on the strip of lawn that belongs to the city that is on the edge of our property. While it could be a rival daycare provider and I wouldn't put it past her...it is also still very likely that it was a city worker who removed it as it is forbidden without some sort of permit or fee. Make sure you place the second one well within your property line....not too close to the street as there is a strip of ten feet or so that belongs to the city and they have the right to remove it.