Would have liked it if the player was allowed to cash out any time during the game.
I went upto 120 mBTC (a few days ago) but went down to 20 after I was forced to play.
It is better to give the player the win amount when they resign than forfeiting everything.
It's a good implementation question - to allow cash out any time?
When it's allowed you should remember that probability of overcome dealer any time during the game is higher, so payout would be lower in that case. It's possible to apply similar rules as minesweeper sites use, but the game would remotely resemble Battleship...
I think the game is more exciting when you are in winning position and you still have to watch the dealer whether he will hit you or not. Or when you are losing and you still have a chance to catch up the dealer. That's a Battleship!
Anyway these game rules guarantee low volatility. When you lose, the lose is not a big one. It's statistically expected that your winnings should be between 31% and 2720% of your bet.