What, get banned because BW keep depositing points? Once is a mistake, this isn't.
Yes, people have got into trouble by spending money that arrived in their accounts, indeed in one example I believe someone was jailed. But the difference is that this is not money and QFF would have great trouble making a case that QFF points have value when their T&C's explicitly state that points have no monetary value. Courts tend to take a very negative view on making such claims and then attempting separately to claim that points do have monetary value.
Also BW would have great difficulty running the line this is accidental given they keep on doing it. The first time might have been a mistake, failure to fix a problem they are well aware of is a deliberate business decision (probably more expensive to fix). The law may well have sympathy for mistakes, they don't have sympathy with organisations who know they have issues but just fail to fix them (and try and blame the person receiving the points).
Note: I have no skin in this game anymore, and aren't one of those receiving points. But don't have a lot of sympathy for BW given their recent history.