HC,
I would imagine using an offset Waypoint routine from a known point in the Database would be out of the question would it?
We will never get away from finger error but double checking entries before punching "Direct" would help I assume.
Landing on the wrong Deck is not the same as landing on the wrong Airport as Airports usually stay pretty much in the same place. Granted Platforms don't wander about very often either.
Rigs, Boats, Barges, and Ships are a slightly different matter.
Ah yes.....400 Pesky peeved Pax.....gets rather crowded in a 74's Cockpit then I would assume!