Yeah that is a big problem. Same people bet the same stuff especially if your a regional bookie.
Imagine being a bookie in the Boston area around '07-08? Sox win the world series, Pats go 18-1 and Celts win their first title in 22 years. I don't know any local bookies really but I'm guessing more than a few got lit up during that period.
that had to be brutal on the locals