For all my military flying career I was empowered to call stop from the FE seat.
I had to un-train myself when I started flying civvy. My first sim evaluation resulted in 2 Swedish pilots and 2 Swedish instructors looking at me in amazement when I called stop on the first take off of the session. I had to laugh when they told me only the captain can call stop. From then on I had to adopt the mentality that we were above V1 at all times and call the failure rather than the action.
Just adds micro seconds to the proceedings with no added safety as I never had a captain continue after a call.