I just finished some tests on the behavior of landing with Terran buildings in Starcraft 1 Brood War.
Here are the results:
-If the building need to move to reach the landing point, and an unit get in landing zone before, you will get an audio message "landing sequence interrupted" (but no text), and the landing won't be done.
-If the building is already at right position, start landing, and you quickly slip an unit under, the building will land, and the unit will start moving to get away (like a SCV that just finished building something)
-If the building is already at right position, start landing, and you quickly slip a tank that will go in siege mode, a zerg that will burrow, or a spider mine deployed by a vulture, then that unit will get destroyed.
-If the building is already at right position, start landing, you quickly slip an unit under, then use Lockdown, Stasis Field or Maelstrom, the unit will ignore the special status and move to get away after the landing (could be considered a bug I guess)
Now based on the section, you may have guessed my question, but how does it work in Starcraft 2?
The most boring, but possible answer, would be that now the landing sequence can be interrupted and reversed at any point and this is what always happen, but even if it's that, I still want to know.