After having tried Cunico's excellent hidden identity addon ( http://forums.bistudio.com/showthread.php?159239-Hidden-Identity-Pack-v1 ) I have thought a bit and want to make the following suggestion.
It would be cool if the "goggles" category could be renamed "Facewear". Further, light shemaghs, balaclavas, along with the existing glasses and goggles should be moved into this category.
If balaclavas are used as headwear, they will not be combinable with helmets. This isn´t really realistic, especially as the fire-protection equipment of modern soldiers often includes balaclavas to be worn under their helmets. (Links 1 and 2)
Additionally, chops for some types of helmet could also be included in this category, as well as maxillofacial plates for crew and aircrew helmets (Links 3 and 4).
Below I supplied an example picture of Cunico's Shemagh on an Opfor soldier to illustrate the advantage of combining facewear with headwear, rather than making the shemagh headwear only.
Existing goggles could then be added as seperate models in combination with balaclavas/facemasks. This would be more sensible than having balaclavas as headgear that excludes use of helmets. {F21008}