Just tested this as planning a trip to Singapore in September. It complained the departure date was invalid, so I moved it back to March and it was ok.
However it doesn't work for Business class - not tried WTP but I assume it works for WT.
Googling talks about BADISCOUNT1 from Germany and BADISCOUNT04 from Italy, not sure if thats the only european origins or not.
Works ex-AMS for sure but I haven't the chance to check more at the mo....