My latest idea to discourage (in the sense of extirpate) stinkbugs is to deploy UV-C lamps in the attic. These are low-pressure mercury arc bulbs that emit a bunch of mercury lines from blue to the far ultraviolet, with special glass or quartz envelopes that don't block the shorter wavelengths (253.7nm and 184.9nm). I'm hoping the bugs are attracted to the light and are then attacked by a combination of nasty UV (which wrecks biological molecules) and ozone (which also wrecks biological molecules, and will vanquish the residual stink). If this doesn't attract them, I'll add some phosphor (BaSi2O5:Pb or SrB4O7:Eu) to downconvert some of the UV-C to UV-A, which is known to attract the little buggers (it's the same phosphor used in bug zapper bulbs).
( pic of apparatus )