I found this explanation, well at least a part of it:
"...Here is what happened: just a few days ago, a member in our forum reported that he was locked out of his casino
account at Rushmore. It turns out that his account was considered "dormant" since it had been nearly two years since he last logged into his account. The casino, like many others, has a policy stated in their terms and conditions that accounts that have no activity for over 180 days are closed and the player forfeits his balance. This player supposedly had 1-2k still in his account - and now it's gone. The thing is, the casino never made an attempt to remind the player that the account was approaching dormancy. They just closed his account and that was that. They stated that they were not going to budge on this.
The bottom line is - is this fair? I understand that dormant accounts can pose logistical problems, and yes, there isn't a reason why these accounts aren't closed. But the casino should notify the member beforehand, and if the member comes back, the casino should offer to open the account back up with the original cash balance. To not do this is unfair in my opinion, and is unbecoming of an "Accredited Casino"...."