This may be on the roadmap already, and just a factor of being in beta, but the other day one of my players pinged me on Gmail chat and said "Hey, I'm in the campaign checking it out; what do I do?"
This is not a problem, except that I wasn't in the campaign, and I didn't know that someone had gone in - actually, I didn't realize it was always live if the GM wasn't there.
I would like to suggest that there be a checkbox on the campaign page that just says "Closed" or "Locked" or something, so that you can prevent others from signing in when you're not ready to play (or so you can allow it, if you need to play asynchronously for whatever reason). I know that as of now, players can't do much at all with tokens or what-have-you except move them, so there's not a lot of damage that can be done.
What might work is this:
1. Be able to simply lock the campaign to prevent access, and
2. Set a notification method - e.g., if I leave a campaign unlocked, and someone checks in, have it email me saying "Player Q has just signed on to your campaign Barbarians of the Tabletop . Click here to open the campaign, or here to notify the player that the campaign is currently closed, and sign them out." (or something like that). Basically, I'd like to be able to determine when someone can be signed into a campaign, and know if someone is there, if possible.
Thanks!