although it's not clearly advertised, UK customers who deposit with a debit card can have the funds back on the same card. you need to do it through customer services rather than automated.
you can only withdraw upto the amount deposited back to the card.
If you deposit $600 on monday and by the end of the week have built your bankroll upto $2000 and decide to cash out they will only let you withdraw $600 back to your card. You then have to withdraw a second time for the remaining $1400 by either requesting a cheque direct from pokerstars or having the balance sent to a neteller account if you have one.
No, this is NOT the case (for me anyway)
I deposited $500 into my pokerstars account recently, using a new Visa debit card that has just been issued to me. I was lucky enough to have a couple of decent wins which took my balance to over 20K, I have since cashed out about $4k back to the same card without any problems.
They do send you a peculiar email though, it says, "Your initial deposit of $500 has been returned to your Visa card, the remainder of the amount you requested will be transfered to your visa card"