使用C ++中的非虚拟公共接口和Scoped锁来避免死锁

I've run into a problem which seems troubling to me. It seems I've found a situation that's easy enough to work-around, but that could lead to problems if a) I have a lapse in concentration while programming or b) somebody else starts implementing my interfaces and doesn't know how to handle this situation.I've run into a problem which seems troubling t