You didn't see the gv dar??
Yes there is a dar but you may not see the LVT. Keep in mind you can resupply as fast as the game resets from drop supply to respawn. As you know there is always a few seconds between spawn in on plane or GV before other players can see the plane or GV which is not a bad feature. Just in this case those few seconds allows a supply drop.
Yes you can drop the CV but LVTs are still available for ten minutes after the CV sinks. When the CV respawns after the ten minutes it can quickly be reset to a feet dry spawn in some cases but not all.
Keep in mind as well the M3 vulnerability on a long M3 run to resupply no matter the spawn. Same danger to an LVT if it does not spawn in to a instant supply drop.
Not saying these are bad players. They just have found a flaw in the game that they take advantage of to the extreme on occasions.