Frequency control at your club
The ham ban would be a good idea whether or not you need it right now. It will only take a little more work right now rather than re-doing everything later.
I also agree with the warning sign as redrocker said. Just be sure to make it big and noticeable. We have one on the dirt road to our field that is brown with black lettering and it can be rather hard to see some days. The excitement of being at the field for the first time can sometimes distract beginners away from it.