I agree and am glad that we aren't the "OpenCaching" site where most of the caches are simply imported from Groundspeak at the click of a button.
Even with a crosslisted cache, I only log it one site. I've now found 61 OCUS caches and most are exclusive, though I don't have the exact number handy. If I do find a crosslisted cache, I will log it here as Found and then post a similar Note on the other site (usually GC.com). If a cache I've previously found on GC.com (or elsewhere) ends up being listed here, I do the reverse. In either case, I "ignore" the other one, so it doesn't show up in my searches / queries.
I also maintain a count of my combined find count and track those as my primary milestones. Currently, I'm at 3006 between GC.com, TerraCaching, OCUS, Navicache and GPSgames.