Well, I don't know if I should do this, but let's go:
1st: They aren't your slaves, man. They are doing that to the community and for the community, not to make people frown and start yelling at each other's faces at every problem down the road. Hell, they aren't even paid for that! Saying "FIX IT!" won't do... But since I think that you came to blurt this 5 seconds after having this happenings to you, it's understandable (at least, for me) and I suggest you to calm down... Take a good ol' Passion Fruit Juice. It's good for tension moments!
2nd: I agree a bit with you, in regards of the invulnerability times not working properly, since you are still mowed down... But it's better than before, being your POV the one mowed down or the mower itself (but in that case, for me, you can't please much Greeks and Trojans. There isn't much of a gray area for this. One of them will step up to critic it, one day or another).
I have a thought for that: What if, besides having time invulnerability, you have for place as well? Like an:
If (time=>1,875s) && (place==spawnpoint) {
invul();
} else {
carryOn();
}
...well, probably the code it's like that, if not sort of... What I'm trying to say is that the invulnerability will both be bounded by place and time. If the newborn entity walks off the spawnpoint or wait long enough, "invul" is a goner.
Well... there's my opinion.
A bit off-topic: Does the spawnpoint have a player detection? That could help in stopping the spawncamp a bit.