No 3, The scrimming up of helmets wasn't just an airborne thing. We had to it with the old tin lid (thank god I only had it in training) and used to attach ripped hessian, old green army towel to break up the outline of the helmet. Before we got the MK 6 and dpm helmet cover. (Apologies if I'm stating the obvious.)
I personally don't think that putting a scrim net over a helmet today without hessian, Blah, blah, blah, to break its outline does nothing other than say I'm airborne qual'd and to look different from the rest of the army. Or the person doing it is walt!