Not banned, they just need to have permission. There are many places around the world, including in the US where US sevice men are not allowed out of the gates without permission. But in my experience the Air force has allways been quick to do things like this.
One place I was at, the installation had an outgoing air force commander, you couldn't leave post without a weapon and an approved pass or leave. The oncoming commander was Army , one of the first things he did was reverse that policy.