I've made the cage on the picture with the following commands:
prop_dynamic_create props_street\police_barricade.mdl (creates the barricade)
ent_rotate 90 (rotates the baricate 90°)
ent_remove (removes the entity you're aiming)
I've rewritten the ent_remove command, now it's protected from removing other players.
Changelog:
v.1.0.0
-inital release
v.1.1.0
+added the cvar sm_buildenabler_onlyadmin (default 1)
so default only admins with the flag "cheats" are allowed to build, rotate and remove objects
v.1.2.0
+added blocking removing the checkpoint door (tested only with the first map of no mercy)