It’s not discussed very much, but during the Normandy campaign a signifigant portion of Germans who surrendered failed to make it to the rear echelon for processing as POWS. This was due to a similar policy from the Germans. There was a lot of Waffen SS in the Normandy campaign and they were absolutely brutal. Regular German landsers were more likely to be taken prisoner alive. SS troops rarely made it to the rear.
On Okinawa the Marines were told to kill every Japanese soldier, no prisoners. My dad had nightmares for the rest of his life. At the end the Japs ran out of ammo and just walked towards them pointing empty weapons