All I can say is that if you do have a meeting to decide your team's policy on inter-school team membership, please push to allow outsiders to be involved.
I went to a very small private junior high school which was able to start up an FLL team. I had a great time and was team captain my 8th grade year. After leaving junior high I have moved on to yet another small private school for my high school education. My school does not have a team, but I still knew I wanted to be involved in robotics, and was lucky enough find a team at my local public high school. My experience there thusfar has been INCREADIBLE and I don't know what I would have done with my high school years had I not been allowed to join the team. On the flip side I believe the team has benifitted from having me on the team, because I have brought a level of leadership and enthusiasm that is needed to maintain a healthy program.
I think that if a student from another school is willing to take the trouble of commuting from school to school to be involved in your program, let them be involved. FIRST is all about opening new doors for students and their futures and it would be shame to close one on them.
If your schoolboard is unwilling to accept these outside students, I would say they just don't get FIRST and what it stands for. So show them.
My $0.02,
Mike C.