It would be nice if you could have a separate "space" to store the coins that we use for gambling and a "space" where you keep the coins for the "income" option. You could offer the users a drop down menu to select the "space" for the different options.

 

I know Freebitco.in can benefit from mistakes like this, so there is no reason why they would invest time into something like this, but it will be a nice feature for the users.    

I stopped using auto-bet, because of this and I think some people might have stopped gambling all together because of previous mistakes like this.