I'm quite astonished to see the amount of traffic that uses airfields as navigational waypoints by flying directly over them at 2050' (estimated!). Common sense suggests to me that flying directly over NDB's/VOR's/VRP's and airfields is best avoided, particularly at around 2000'. Why don't pilots navigate with some sort of offset from the feature that they're using ? Actually, thinking about it, the more pilots who navigate this way, the safer it is for me as I avoid such hotspots!
Laziness?
Navaids and airfields are all in the GPS database under their normal ICAO code so it's easy to string a bunch of them together to make a route, then follow the magenta line.
(VRPs are a different matter. Most GPS databases have a limit to the length of a waypoint and a VRP like "South Woodham Ferrers" has to be abbreviated, which doesn't happen in a consistent way across GPSs and GPS manufacturers, or omitted altogether.)
But even without GPS, navaids are intended as navaids: string them together to form a route, then fly the route with fairly simple nav equipment. And airfields are rather easy to recognize and identify from the air if your nav is purely visual/DR.
But I agree that it concentrates the traffic, particularly in busy areas or areas without much else to base your navigation on, onto a single point in space. Flying offset (in case of a GPS not that hard to do, just make sure the cross track error is constant at 1 nm or so) would make a lot of sense.