private bool Forbid(PerModeSettings perMode, UnswitchChoice choice)
{
if (choice == UnswitchChoice.Always) return true;
if (choice == UnswitchChoice.Never) return false;
bool ret = false;
if (choice == UnswitchChoice.LatePhaseOnly) {
if (perMode == null) return false;
ret = (GetPhase(perMode, false) == Phase.Late);
}
return ret;
}