I have got -98 E46 and -98 E39 and both had that same airbag problem. They were fixed by BMW by changing some wires under seats. Both cars had that issue several times. I have red these BMW forums in different countries and everywhere exists this same airbag thing no matter what model or modelyear. That is so sad they can't fix it. And now again. I am seriously rethinking what I am gonna buy. Really can't stand those BMW airbag problems anymore.
And yes, I asked this "lemon" thing and they thought I was crazy or something. They told that it is so sophisticated system that it can be different problem everytime

. And because both cars were few years old I should expect somekind of problems with the cars

. Well, not that kind of problems, I think.