city of Chicago Off Limits sticker

[Robert D.]

sometimes when I do research on a properties I see building code violation regarding abandoned building. they are standard and : 

CN193000	Maintain building in safe condition so it does not constitute actual and imminent danger to public. (13-12-130, 13-8-100, 13-12-120, 13-12-125, 65 ILCS 5/11-31-1) Maintain building windows and doors in safe condition. (13-196-550) Maintain stairway and porch in safe condition. (13-196-570) Maintain floors, walls, and ceilings in safe condition. (13-196-540) Maintain building in safe condition. Premises now dangerous as vacant and open, uncompleted and abandoned, or vacant and boarded. (13-12-130, 13-12-125) Maintain watchman at vacant or open premises. (13-12-140)
CN193019	Repair or wreck dangerous and vacant residential premises. (13-8-100, 13-12-125, 13-12-130)
CN193029	Maintain watchman from 4:00 PM to 8:00 AM for vacant and dangerous residential premises. (13-12-140)
CN193110	Register vacant building within 30 days of it becoming vacant, or within 30 days after assuming ownership of an existing vacant building. (13-12-125(a)). Building must be kept in compliance with all vacant building requirements pursuant to 13-12-135. See Vacant Building Ordinance and registration form at https://ipiweb.cityofchicago.org/VBR
CN196039	Post, on abandoned building, name, address and telephone of owner and owner's agent for managing, controlling or collecting rents on building so legible from nearest public street or sidewalk. (13-12-125)

...but sometimes I see also a yellow sticker on the building. the building does not have a red cross on it. is the yellow sticker indicative of some major damage such as flood, extensive fire damage or structural damage ? why would a city inspector put that sticker on 2 out of 10 empty houses...what drives the action ?