[RightDeve]

In other words: yes, Steel Panthers by Camo Workshop has a mechanism for thwarting PBeM cheats, like what you said, re-loading.
If you're afraid of an opponent cheating, use Secure PBeM instead of a Basic one. It's not that much complicated from the Basic security, once you get used to it you'll make it the default way of playing against PBeM acquaintances.