The Grammar Hammer embraces misplaced commas

Today’s Comma-D of Errors, from FreeWood Post:

“The Russian Embassy was trashed today in D.C. by an angry mob of inebriated men who showed up from the neighborhood bar across the street thinking there was a promotion for “Free Pussy.” They commenced to start a riot and trashed the place but were disappointed after discovering that there was no free pussy.

“It seems there was a misunderstanding when protestors were standing out front with signs reading “Free Pussy, Riot”…”