Let me come at this from the perspective of a landlord and as a former Home Owners Association (HOA) President.
From the landlord's angle, I prohibit the display of any signs or banners on the property without permission. I did this because tenants were using random flags (not US) instead of buying drapes or blinds, because they put up all sorts of weird political stuff that pisses off half of the community and leads to vandalism of MY property, and because experience shows that they rarely take care of stuff after it has been put up and/or leave it up past expiration (political signs still up in Jan when the election was last Nov, etc.).
As a former HOA president, the original rules prohibited everything. But these were home OWNERS in a exurban area inside of a GATED community. Like
Variable, enforcement of certain rules pissed me off to the point that I did a hostile takeover of the board and became President. My first act was to revoke a hair over 1/3 of the rules. That ended the ban on flag flying, the posting of signs at or under a certain size (with an exemption for ANY size sign for 7 consecutive days or less and active Realtor/for sale signs), and ended the ban on home occupations.* Still, 2/3 of the rules were kept in place. Those were the rules that involved your neighbors. Basically, I was all for doing what you wanted so long as you didn't screw with your neighbors or their property values.
*So have I ever told anybody about how Distinction Arms got its start..?
Any how, I understand the apartment managers' position. However, they're forgetting rule #1–– CONSIDER THE CIRCUMSTANCES BEFORE BLINDLY INVOKING RULES. Certain things can - and should - be overlooked. This was one of them. Back in the beginning, I would've either overlooked the violation or offered to have a professional huge flag pole put in that they could tend in exchange for "not using the flag as a drape." None of this would've ever happened and life would've been good.
Zero tolerance means zero brains.
Mike