SP
I think there are many definitons for a safety pilot.
One, he or she could already be an ATPL or CPL with IR with FI license and been checked out to fly on the right seat.
A safety pilot is a qualified and rated guy for the type of equipment.
A safety pilot is the one who takes over if Student paks-up on what he is doing.
A safety pilot is somebody who takes control if the Student is no longer qualified to shoot an specific approach.
My point is, even Airlines assign Pilots as Safety pilots.
There is really no Illegal here or being unsafe, because in the very beginning of the word it says " safety" pilot.
So, how can a safety pilot be an unsafety pilot?