Well, not exactly. Assuming we are discussing of the GSX vehicles, they will use this strategy when deciding where to go (or *from* where they appear)
- If a parking of the kind "vehicle" is found within a reasonable distance from your parking is found, they will use that one.
- If no parking of the "vehicle" kind is found, a random parking will be used, provided is not too close and not too far to your location.
- If no parking of *any* kind is found close to your location, any random parking will be used.
And, the same is valid to decide which PATH is taken to arrive and return. Paths of the "vehicle" kind are being given the highest preference but, of course, if there's no such path in the AFCAD, we cannot obviously let the vehicle being stuck somewhere, so we'll then use apron path, then taxiways and, as the last resort, runways.
This means, if the vehicles don't go where you think they should, or taking paths they are not supposed to take, it's usually because the scenery developer has forgot to include some vehicle parkings close to the main terminals, and/or forgot to connect them to the rest of the airport layout using path of the "vehicle" kind, so GSX is forced to use other parkings and routes.
So, the real question should have been:
"Why the developer of this EDDP scenery haven't added a vehicle parking close to the DHL Warehouse, which is probably there in real life, so that GSX vehicle can take realistic path to arrive/go away ?"
