Cameras (speed/red light/combination/dummy) are lockable at a selectable level. The minimum lock level for a camera should be locked at the same level as the road segment on which it is placed. (Speed camera on a Major Highway (MH) will have the same lock level as the MH; lock levels vary by region but most will be L3 or L4.)
All cameras should be locked to at least L2, even if the road segment is locked at L1. The reasoning behind this exception is when a camera is reviewed and properly placed the L2 level will indicate that review. This is similar to raising the lock level on a properly review area place or point place.