Found this on a number of British blogs. For more, you might want to start with Nosemonkey.
In particular, the pack might have been saved five tourists in New York yesterday, as reported by the NY Times.
Oh sure, I feel SO much safer.
UPDATE: This incident has drawn an apology from Mayor Bloomberg and some recriminations between Gray Line and the NYPD. Today the Times published a picture showing tourists led off the bus with hands in the ari:Welcome to New York!