And this is something, which I find kind of "unfair", if that makes any sense. I know there is no way around it, but it's the same scenario. It's just that I am a private person with no T&C and no possibility to cancel/void an accepted bet, while bookmakers are always protected by their T&C and can basically do anything they want. Something which @Upgrade00 stated as well.
It can be sound as a silly difference, but this is the difference. When you bet in a bookmaker you're accepting their T&C. And these are designed to help and prevent at the most any loss for the house. We should remember each time that bookmaker are company that should have profit.
If it was very easy win with betting, no one was offering this kind of stuff.
Or as I have seen in my country (monopole) horse with odds of @1.00 ! Is it unfair? Yep is it!
Since if you win you get money back, if you lose ....
Also in my country some website have banned good better, or live corned due AML laws decide to avoid people to make large bets (over 500 euro).
They know very well that these type of better are very dangerous for their business, so they should find any excuse and exclude people from betting!
But is not for all. If you lose no one will complain, and you are allowed to place large bets.