I didn’t day it did. But the Geneva Convention made an effort to “civilize” warfare and such actions by Sherman would have clearly been “uncivilized” according to the consensus of most people at the time the convention was signed.
I agree that what Sherman did, using prisoners to probe for mines, was uncivilized.
I will also hope you agree that what Wheeler did, planting mines that would resonably and forseeably pose a significant hazard to civilians after the war was over, was also uncivilized.
The difference: Sherman gave his orders to bring Wheeler back to responsible behavior. It worked.
I will also note that when Germans in WWII destroyed their maps of minefields, and in the Falklands when Argentinian commanders destroyed their maps of minefields, prisoners were forced to probe and remove mines.
One way the Geneva Convention works is by reciprocity. If a party violates it, it removes a corresponding protection from the side that violates it.
In like manner, illegal combatants are not granted POW protection by the Geneva Conventions. Rather the US extends POW treatment as a courtesy, as an example, and as a means to gain intelligence information.