World Cup-Brazil
NBA-Detroit
NHL-Ottawa
NFL-Indianapolis
MLB-NY Yankees
NCAA-UCONN
All favourites, all losers, so do me a favour and go screw your head back around, and please don’t talk to me anymore, unless you’re trying to make me laugh, i’m not in the mood
Firstly, if you could tone down the belittling nature of your posts, it would make it much easier to have a discussion on this topic.
Now, do you understand what a favorite is? You say Indianapolis was the overwhelming favorite last year. Yes, they were, if you were thinking about the odds to win the superbowl, but we’re talking about each individual game.
For each game (straight betting) in the NFL last year, the team that was laying points (the favorite) won and covered the spread more than 56% of the time last year. Now, you should know that many handicappers would give their left nut to pick 56%. So the fact that this many favorites covered is quite an aberration. Now, it is will known that the casual bettor likes to bet on favorites. So the fact that this many favorites covered the spread means that the bookmakers who catered only to “square bettors” (the casual bettor) either A) lost money or 
earned significantly less money.
Yes: there are sportsbooks that cater to squares. The first ones that come to mind are the (now defuct) BoS family, Bodog, Nine, Bet365. These are the books that will either kick you out or severely limit your bets if they believe you to be “sharp.”
For clarification to those reading, “sharps” are those bettors considered to be professional handicappers or good at handicapping, whereas “squares” are those 95% of bettors who are long term losers in sportsbetting
And your assertion for the other sports does not come into play here. I was referring to the NFL season of 2005-2006. And you know as well as I that the bulk of a sportsbook’s volume comes from football. The NFL is THAT big.
You are correct that many sportsbooks would like to have even action on each side. You are also correct that if they achieve this while at the same time only catering to those bettors that neither lose massively nor win massively, the affiliate gets screwed. But the fact of the matter is that the sportsbook world does not work this way.
Everyone is not going to go 50-50 against the spread every 100 games and piss away the vig, thereby screwing the affiliate. There are going to be players who go 30-70 ATS (who lose money) and there are going to be players who go 62-38 ATS (who win money). And this is why many sportsbooks are not going to pay you on a percentage of bets made basis. They want you to bring in people who go 30-70, 35-65, ANYTHING that is less than 52-48 (breakeven at -110 pricing), because they earn money this way.
And this is before we even start talking about parlays, teasers, and all the rest of the stuff where true “even action” isn’t even possible.
As far as your situation with Bowman’s, unless your site targets those big bettors that lose their ass (and there are PLENTY of them), I’d go ahead and dump them if you have a negative rollover in the thousands. There are plenty of other sportsbooks out there that function in much the same way as Bowmans (clone lines, moving on air, etc), so you may as well direct your customers to a place where you don’t start in the hole.