[jp10]

What specifically started this subject for me was historical scenario battles (understandably more available in WW2, MBT has many hypothetical battles) like the Wolmi Do landing (136 captured) 2nd Para in Darwin (1000 prisoners) and the battle of Asal Uttar where after the end of the battle a Second Lieutenant leading a team of 20 soldiers searched a sugarcane field and shouting out for those hidden inside to come out – the Commanding Officer of Pakistan’s 4 Cavalry came out along with two majors, one captain and 17 other ranks to be made prisoners of war.
I have tested these battles and other scenarios that had a notable POW tally several times and only rarely have units surrendering. Holding their positions, pinned or routed till they disperse (and using up my ammo) yes, but routed, HQ broken and in contact with my forces they still refuse to wave that white rag.

The requirement to be encircled is too constrained in my opinion. I offer that a routed unit with an adjacent enemy unit triggering a surrender check would be an appropriate standard. If they don't surrender then (Hande hoch! Waffen weg!) then they can be fired up.