One thing to keep in mind is that ground spawns, when we imported them from the EMU community back when we started up, sometimes has the z-axis wrong. This can cause items to float above ground (you may have seen some floating tradeskill containers like forges or ovens do this). Given that there are thousands of stationary objects and groundspawns throughout the world, and floating a little above ground is odd (and sometimes kinda funny) but isn't game-breaking, it isn't too high a priority to fix the z-axis for all of them.
All that is to say: when you're searching for a groundspawn, look not only on the ground but a few feet above ground as well (maybe as high as head-level on a normal sized character).