[Terr_]

Wouldn't it be funny if they are the same flags, and instead the perpetrators bleached them "remotely"?

Like with a quad-copter hauling loads of liquid bleach, or a laser with the right wavelength to destroy the dyes.

Edit: Ah, never mind, the spotlights are also up on top, not down below as I had thought. It'd take quite a lot of robo-dexterity to cover them up so quickly, so if a person is already up there they might as well just swap the flag too.

[rotten]

Or some nearby industrial plant belched a cloud of toxic bleaching gas that drifted by and as a side effect reacted with the cheap chinese dyes in the flags.

Corporate terrorism? It would never happen...