True, but it would've been kind of cute if they "saw too much" and ended up making another appearance, kind of like the opportunity to re-use a later character who really likes donuts and bowling. But there characters weren't really developed enough in the episode to justify it, and probably half the episodes have characters who we could imagine showing back up but who don't. I guess the other half of the episodes do
have characters who show back up. ^_^
I guess I'm saying it would've been nice if a few more normal
Earth people found out the secret and got pulled inside a few times, or had odd specialties that ended up being needed off planet. As the audience we'd be likely to identify with ordinary Earth folks who also end up traveling through the stargate, a bit like Samantha's father Jacob (though he was an Air Force general) or Ely's character on SGU, as opposed to all the ordinary folks from other
planets who had the wonders revealed to them.