My favorite TROP knee-jerk thread occurred earlier this summer. Some poor bloke had the misfortune of being beheaded on a London street in broad daylight. Hours of, ahem, ethnically- and religiously-based speculation followed, until it was discovered that the event was the unfortunate culmination of a homsexual lover's quarrel. I'm sure even Mullah Omar had a laugh over that one.
Most of the thread was about blaming Muslims or Mexicans when it turns out the suspects were French.