Responding to a comment by ben, and to the general suggestion that the whole incident may have been scripted for some dark purpose, I wrote:
For maximum evulz, they had to get someone sympathetic enough to become a "hero" but obviously-bad enough that those lionizing him would be knowingly celebrating evil. GF, who had done some seriously bad things (such as threatening to kill a baby during a home invasion) but in this particular case was under arrest for some bogus petty non-crime, fit the bill.
This was a reference to the TV Tropes term "For the Evulz," -- referring to villains who have no motive beyond being evil for evil's sake -- and for some reason immediately after posting it, I randomly decided to run a Google image search on evulz. The second result was a "motivational poster" style meme featuring Heath Ledger as the Joker from The Dark Knight. (The archetypal knight, solidified in that role by Edmund Spenser, is St. George.) I clicked on it, and one of the "related images" caught my eye.
"Twenty bucks." "But you'll kill me." It's from a 2008 Batman comic book, so well pre-Floyd. My finding it immediately after posting about GF and the $20 bill was the result of a completely random whim.