I've just had a look in both Blaster Law and SM:P, because the OP's issue has always bothered me a bit too (so far I've gotten away with it by the players just not thinking too hard about it!) In neither of the skill descriptions of Suppressive Fire does it actually say you lose any DB - or even mention DB except doubling it for cover. The closet is comes it so say if you don't dive for cover you "chance being hit".
Now, I don't disagree that that's not a good idea (believe me, my party has shocking DBs and half of them have shields nowadays). Was that actually the intent of the rules? As I say, the RAW (rules-as-written) don't seem to suggest that, except in a rather round-about way.
Certainly, my interpretation of Suppressive Fire did not, until yammahoper's post, ever even consider that to be a possibility.
If that was the intention (or even if it wasn't it's a damn good idea), maybe it should be added into the FAQ or the errata. It does actually make Suppresive Fire dangerous at mid-to-high levels again.
