The restricted bastion was created long ago back when we recommended ssh agent forwarding for VM access. Out of an abundance of caution, we had people with root keys forward through a separate bastion to avoid the risk of key sniffing.

We no longer use forwarding, and haven't been especially compulsive about segregating ssh traffic between the different bastions. We should just eliminate the special bastions and standardize on everyone using standard public bastions; this will slightly simplify our setup and also ensure that admins are drinking the same champagne as our users.