Gabe's story reminded me of a situation way back in the 80's in San Diego. Some of the team guys had a habit of stalking in certain parks in the area. It was rumored that new guys were frequently given these missions to sneak up on civilians. The park police guys had an extremely hard time tracking these guys down. The frogmen-in-training were using state of the art T,T,P's, while the cops were just using basic LEO techniques as taught at the time. Luckily no one was hurt, as far as I know, so these incidents were kept quiet. But, just goes to show, this is the level of opponent that is quite possible to run across.
Having NV to see in a situation such as these, is huge. Being able to see first, and get inside a guy's loop, is a significant advantage.
As regards to fighting with it. You have several scenarios here. At long to medium distances, you can stay on NV and fight. At CQB distances, you may have to come off the tube in order to go hands-on. If your opponent goes to white light, you may have to come off it and fight with red dot and/or your own white light.
Ideally I think the head mount is the best solution, in conjunction with a IR laser mounted on the rifle or pistol. I think Gabe's idea of a neck lanyard makes a lot of sense. If the tube is bumped and comes off the mount, it is still around the neck, and can still be used by hand, especially with a pistol. Or time permitting, it can be re-mounted on the head. The standard "Rhino" mount has a break-away feature that allows the tube to dis-connect without breaking anything. So having a neck lanyard to catch it, versus a safety cord tied to the headset, puts it in a much more usable position.
The Crye "Night Cap" is a relatively inexpensive way to get into a head mount set up. Without going into a full helmet set-up, it gives you the same hands-free operation at a fraction of the cost. Much more comfortable than the old "skull crusher" mount. Also works very well when proned out for extended surveillance, as opposed to a helmet which may limit your range of motion.
A Wilcox IR filter lets you wear the tube at a stand-off position, which allows you to have good peripheral vision around the tube eye. The filter cancels out the "raccoon eye" of green back splash against your face when not using an eye cup. This allows you to have much better near vision for movement, without a blind-side. The field of view is slightly smaller but well worth the trade-off IMHO. You can accomplish the same thing by simply rolling back the eye cup and moving the tube outboard, but if the oppo has NV, you may be getting visible backsplash.