The story of a Russian soldier successfully surrendering to a drone is here.
The Pioneer UAV from the First Gulf War is here. And you can see it in person at the Smithsonian Air and Space Museum.
The F1 Grenade is here on CAT-UXO.
The VOG-30 is here on CAT-UXO.
We may need to consider a fifth Geneva Convention which would outline the procedures for surrendering to and accepting surrender from unmanned vehicles. This may be a case where technology has outpaced the law.
Drone Warfare and Surrender