Same thing happened in Halifax about 2 years ago. My campus bar used to have $7 pitchers at happy hour, and they ha an annual birthday event where the bar opened at 7, sold drinks for 35 cents or something like that, and raised prices by a dime every 15 minutes. It was carnage.
Thanks to a couple brawls on dollar-drink nights at the greasy clubs, the city raised minimum drink prices to $2.50. Campus bar now charges 3.25 for a happy hour pint, and 11.50 for a pitcher. Though if you know the bartender, they'll usually sell you a pitcher of "overpour" (beer that leaked out of the tap, excess foam that got dumped off pints and stuff. Flat, warm beer) for around $5. Though it's not a pleasant drink...