Been thinking about this lately, on one hand a lot of random ass people we don't know join the group which is confusing, especially for new members. It's handy to have the group because we can easily link someone new to steam and they can add all of us in one place, however if there are a bunch of random ass people in the group this is kind of meaningless.
On the other hand, without invites it makes it so people we know can easily join the group and stay in touch.
I'll put it to a vote, also if we made it invite only, then anyone who is friends or affiliated with war would be invited to/allowed in the group, not just members (this is helpful for prospective members who want to meet everyone). This isn't to close non-members out, just to make it so random people that none of us have ever encountered can't join.