Not sure I understand what "fixed odds" betting is anymore ... just saying ....
Ie if I bet on say on the NBA and multiple players drop out the odds don't change from the initial "fixed odds" bet I placed ...
I could have bet on players rebounds, points scored etc ... any player out would affect the odds you'd say ...
Why is horse racing any different ?? or does the same happen in other sports ??
Edit: account now closed with BetEasy...
You're not quite comparing apples with apples.
When you bet on the NBA, say Joe Smith to score 20.5+, and then Ben Jones and Frank Furter pull out of the game, you still get your odds, as even if Jones and Furter are the teams leading scorers, you can't quantify what affect that has on Smith scoring 20.5+ or not.
Now lets' look at an exaggerated example in racing. A 3 horse race. The actual formula used can be complicated, but lets look at a simple example.
In this 3 horse race Anders is $2, Beaker is $3, and Chaser is $3.5.
The betting has been solid, and at the barrier, Anders plays up, knocks his head, and has been scratched.
Bookie Ben Dover had made a beautiful Bookmakers book. In total he had laid bets totalling:
Anders $10,500 - pay out $21,000 if Anders wins
Beaker $7,000 - pay out $21,000 if Beaker wins
Chaser $6,000 - pay out $21,000 if Chaser wins
This sort of "balanced book" is what Bookies aim for, but realistically never achieve.
Now, Anders has been scratched at the Barrier, and now there are only 3 possible results. Beaker wins, Chaser wins, or a dead heat.
As you can see, this is different to your NBA bet, as the players dropping out haven't affected the number of possible outcomes on your Joe Smith line bet. He still either gets his line, or misses it.
With Anders scratched, the Bookie has to refund the $10,500 bet on him, and when Beaker wins the race, if there were no deductions, he also needs to pay out $21,000 to the punters who backed the winner. He pays out $31,500 in total, after taking $23,500, and loses $8,000. This is totally unreasonable. The conditions of the bet have changed, and the number of possible outcomes has been affected significantly. Note the difference. Racing bet, number of possible outcomes altered. NBA bet number of outcomes unaltered, but chances of success greatly altered. The Bookies will in all likelihood drop the price on Smith going 20+, or conversely, push the line out to something like 30+. They have no recourse to alter or amend the bets already placed.
What happens is, after the race the Bookmaker's Supervisor determines all bets on the winner, placed BEFORE the scratching will receive a deduction. Anders represented 10,500 of the total 23,500 market, or 44% of the market. The deduction on bets placed on the winner are paid less $0.44 in the dollar.
Let's see how that affects Ben Dover's book.
Total held $23,500
Refunded $10,500
Winner paid $21,000 x 0.56 = $11,760
Ben Dover wins $23,500 - $10,500 - $11,760 = $1,240.
Before the scratching of Anders, Ben Dover with his perfect book, was guaranteed of winning $2,500.
It's a perfectly reasonable approach, and different to a line bet situation.