Re: Neteller - I've had experience (and I'm sure others have too), of a casino paying me twice and then taking the extra money back from Neteller when they realised. Although I was shocked they were able to take money from my account without informing me (and lost some trust in Neteller), they had a fairly strong case
This issue here is a hundred times worse. It looks like two weeks after the fact a casino can persuade Neteller to allow them to take money from someone's account for a mere technicality, with the casino taking no responsibility for their previous actions (actually I'd love to know what they told Neteller - I'd be very surprised if it was the same explanation we've been given here).
As others have mentioned, this is the casino equivalent of a player making a charge back. It shouldn't be possible, and wouldn't be with most payment methods. In the current situation Neteller can't afford to alienate their customers, and they need to rethink this issue. These chargebacks, if allowed at all, should be restricted to blatant errors (e.g. paying someone twice). In any case the customer should be contacted.
Otherwise Neteller's Achilles' heel - their being so dependent on casinos - could be their undoing in areas other than North America (a lot of players are already wary of keeping more than minimum funds with them).