gogo - You've been around the block. Players take shots at books all the time playing bad numbers or after games have been started. None of the books confiscate deposits as a punishment. They cancel winnings. DirectBet confiscated a deposit and that should never be done.
You mention two situations where the book has made an error, or in the case of a "bad number" at least claims to have made an error.
In those situations, a player could legitimately not know the start time or not know the market line (many only use 1 book), and so I have pretty much always sided with the player in those circumstances and generally have felt that the bet and deposit should be paid unless a serious attempt was made to notify the player and the book is also going to refund losing bets that were also made after the game started or losing bets on the other side of the "bad" number (and the book can then 86 the player after they pay him if they don't want to deal with him any longer).
As you may recall, when a new book appears, several times I've posted in this thread pointing out language in their T&C which is questionable, such as "We can confiscate funds if a player is part of a betting syndicate" and other such egregious language (which to me is simply scamming/free rolling on the book's part).
In the case of Anonibet, I persisted on trying to get them to clarify a vague statement that if a player deposits and doesn't bet and then withdraws, they can keep 5% if they wish. Etc.
And in a number of cases, books did then modify their T&C to make them more "player friendly".
So I am or have been opposed to anything that can allow a book to take a shot at a player.
Btc books have a circumstance that is new with bitcoins.
Double spend presents a new way to scam, as in the case which Directbet alleges.
If a person tries to commit credit card fraud or bank fraud with checks, etc., this will ultimately result in criminal charges by the bank or the cc company.
But with btc, a player can takes shots at businesses accepting btc all day long.
Perhaps, as you feel, the correct thing is for the business that catches an attempt at a doublespend to simply state "We caught you. Here's your btc back."
But it seems then the scammer has nothing to lose, and for that matter may as well try again.
If the business instead states "We caught you. We're keeping your funds because you tried to cheat us", this would be a strong incentive for scammers not to mess with them.
I've never thought about this until now, and wasn't even aware of doublespend until now, but these are my initial thoughts on this type of situation. So I'm basically stating that I can see the book's point of view on this issue in a case where it is demonstrable that the doublespender was scamming.
Apparently in this case due to all Directbet has stated, this person has a history of this, he didn't deny it at first and agreed not to do it again, the way the doublespend attempt was made seems to be demonstrable, etc.
In this case, Directbet is willing to return the funds, conditionally. So it appears to me they're making a compromise and their primary goal with this incident is not to steal the btc.
I realize that this rule opens the door for books to take shots at players if there is an accidental doublespend. I don't understand how that happens but if it does occur, it could create potential future conflicts.
What would you do if you were a book and someone tried an obvious doublespend?