Trying to depict a surprise affect, I came up with the SSR below. The context is Norwegian ski troops coming on board behind a hill and not likely to be in the immediate LOS of the Germans.
>>>
4. Provided all Norwegian units on board have remained concealed since entry, the first Norwegian infantry unit to attack a German unit will cause an immediate PTC of all German infantry in the LOS of the attacking unit (resolved prior to resolving the attack). This can occur only once.
<<<
Is this clear and practicable?
I don't think you need "on board"...as there is never any LOS to offboard units anyways they are always effectively ? as they are LOS.
I would have it read "....to all.." vs. of all...it is a little more active construction...[minor I know]
I think you need to say whether the actual attack has to be rolled. What if the Norwegian unit (player) is SOOO satisfied with the PTC effects? thus add "....resolving the attack, the DR to which must be made regardless of the PTC effects.)
Are free LOS checks allowed to see if the Germans are in LOS of the attacking Norwegian units causing this PTC????
Should this PTC really effect Germans at >= 17 hexes??? often a sort of things get hazy to LOS range of the MKI eyeball...
[I don't know the playing area maybe its 1/2 a board so a moot point or are we talking Action at Balkenkamp here??? ie 4? boards of play????]
Practicable...seems fine really. Like a "OH MY GOD we are being shot at" moment.
The downside is that if say the Nor. player Adv, his guys into position to spring the trap....the German will simple in his Prep Fire fire at that unit, hoping to strip "?" and thus avoid the PTC b/c the show is on the other foot.... I have no details of your scenario...but it seems perhaps hard to actually implement b/c of the above....but* I could be wrong...nonetheless I like the concept for sure.