Alien Crackers - no, sounds too much like Animal Crackers. :Q
Alien Crackheads - No, too confusing.
SETI Converts - No, too permanent 🙁
SETI Cavalry - ??? Appropriate 🙂
SETI Calvery - is the pun too obscure outside this context? 😉
P.S. No, I'm not joining the [edit]mini-[/edit]team. I just came up with all these great names! 🙂