I thought when the carrier was killed or bailed too soon, the troops no longer can capture the map room.
I am nearly certain that as long as troops are released laterally within 2k of the map room they will run. Same rule applies if air dropped, altitude doesn't matter. I've dropped those suckers from 20k in a goon and they float down and capture bases. Now if you re spawn while the troops are running you will lose them, but as long as you release troops, tower, and sit patiently for "base XYZ has been captured", those puppies will go undetected, and yeah it's definitely pretty "gamey".
Although I often use this tactic, it should be fixed.