Sure it's casinos own decision, don't really see rogue point there if they only block account and pay all balance including winnings.
Also like some mentioned earlier, there are really different situations that only receiving benefits is no reason to block your account if at same time have proof that you won big from lottery and have that money on your account etc...
It's not only magic word benefit but over all how your bank statement is looking. Like said earlier, i personally would block player who is living only with some small benefit, you can't let them play lot anyway and all you can get is possible troubles as people with unemployment benefits don't usually bring you many coins but possible troubles if there's not some extreme strict limit to prevent player overspending.
At that moment when you know players financial situation, you can get troubles by ignoring it and by letting player deposit even little bit over tenner (or what ever amount is counted to be too much to spend from that disposable income), as long you don't know that player is on unemployment benefit, you can happily let everybody deposit few hundreds a month and you don't do anything bad, as long spending is not that high that you fail to request sow etc...