House Sparrow question about "decoy" feeder

I've been reading a lot on this board about HOSP issues, and have a question. I know that many say that doing a "decoy" feeder only encourages them, but here's my situation.

Our large lot, though beautiful, and in a subdivision with ample greenbelts, backs directly to the backside of a major shopping center. Super Target, fast food, dumpsters, the works. Consequently, I don't think trapping or completely getting rid of the little beasties is going to be an option for me. I don't even think they are nesting in my yard, and I've looked. I think they are coming over to feed and use the birdbaths and fountain, but nesting in the eaves of the commercial buildings out back. There is no way I will ever make a dent in that.

I also have a good many mourning doves and white-winged doves, who I feed cracked corn and cheap bird seed at the very back of the yard daily (some in a platform feeder and some just spread around.) So long as I do that, the HOSPS stick to the back mostly. The moment I let the cheap stuff run out, they start coming closer to the house to investigate my other feeders. I rigged a halo on one, which helps a lot, and they don't bother the thistle feeders, and so far (knock wood) not the mesh peanut feeder or NONO cardinal feeder with BOSS/safflower either.

So my question is this: the conventional wisdom I've read here is DON'T FEED THEM, period. NO CHEAP SEED!! But in my location, it seems that having a cheap seed "decoy" area in the back of the lot actually gives the birds at my main feeders some peace. Am I asking for trouble to continue doing this, or just making the best of a bad location?