Well, assuming XDeathwing is guilty of owing the .50 BTC, it was essentially a bounty. Its not often that people put bounties into escrow or anything, so had XDeathwing not been staff, it would be the same situation, someone who reneged on a bounty.
As for how long XDeathwing was a member, they are a local mod on the Turkish Board. If they speak Turkish and reported a lot of posts accurately they could have got the position. However, you are right the staff tag does give a bit of credibility just because of the title, the same way that hero member used to. But I don't think going back on your promise about a bounty is something that people do intentionally if they have something to lose, so I'll be watching for progress when XDeathwing logs on.