ikeadm currently checks that a user is properly authorized by doing a poor man's test for root. It tries to open a door file Read/Write that is owned and readable by root.
Dr-------- 1 root root 0 Nov 25 13:48 /var/run/ike_door
If ikeadm talks to in.iked through the door, in.iked acts on its behalf.
It should follow an authorization model where the authorization is enforced by in.iked itself, by checking the authorizations of the user.