Spawn points are not marked on the surface, thus the defender has to do a search in order to pick it up precisely. While he does that, he is exposed to enemy fire.
Usual situation when you find spawn campers is after a failed ground attack on a base. It is extremely rare (I am yet to see it) to see a spawn camper on an unattacked field. So, from my point of view, and having the ground attack assumption as correct, the first mistake is not blowing away the VH, the second is failing in the ground attack, and the third and final is not having air cover at the spawn point.
Beyond this, If a respawner is killed by the spawn camper, he has to asume that his attack has gone nuts, and find another suitable strategy/suitable spawn point/suitable airfield to attack, instead of having a random spawn point to counter his lack of preparation.
A well planned/well executed attack, with the current MA situation, is nearly unstoppable. A poorly planned/executed is often (not always) led to failure. From my point of view, the lack of a sound plan or the failure of an attack should not be favoured by any means.
Just my .02
Pepe