I think, for me at least, asking for a working tank is like asking for an alien blaster. Sure, everyone wants to find you one, because being on the Maestro D's short list for the next party is a good place to be. Thing is, it just doesn't exist, at least as far as anyone knows. Now if Balls shows up with a ray gun or the local warlord rolls out a tank, the Maestro D' can say she wants that particular item. Then it comes with its own consequences when Mox comes rolling into town with a tank gunning full speed to stay ahead of the previous owner's enforcer gang. Or even ok, yeah, its yours for now. No one knows who stole it and gave it to you. Of course, if the owner finds out you've got it. . . well, that's the hard move for a missed roll.