Generally speaking, I find many of the rules given by different legislations ridiculous, but if you couldn't cancel your pending withdrawal in a casino, then I see it as a great step in order to protect players from losing their winnings. We all know this is a widespread issue.
When you create a payment order in your internet banking, you can't revert it as well so I don't see any issue with this measure. If you decide to carry on playing even despite the pending withdrawal, you can still make a new deposit. If it's supposed to work as I described it here, then I like it a lot!
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