No, I have always been paid. I have heard of this happening to other people though. I have always worried about that though. But so far so good. Now that we can't play here in the states now, I guess I don't have to worry about it now.
I've never had any problems getting my money, but I've had a few waits as cheques have winged their way across Europe. It does happen - there's a number of people over at the Bingo Players Union who've had issues.
I have never played poker online. But I know my father used to and one time he went to collect his winnings. It was for 105.00 and he never got the winnings. That was the last time he ever played on the internet.
That's why it's important to read the terms of serivce agreements that you have to tick off in order to play. It will explain there the payout system and sometimes it really sucks. I played at one site where you had to amass $2500 in winnings before you could request payout, and then you got it in $1000 bundles ...one request a month. Never went back after reading that!