I've only seen the BAC advertised for use with the ACOGs that have the light gatherer on top.  The BAC is basically looking with both eyes open using the weak eye to scan the distance for the target and once on the target, the dominant eye takes over with the magnification, right?

That is what I understand it to be.  Although I think any scope with a lighted reticle could be used if it lit up bright enough.

I have been practicing with my TA11 for about a month now and going from left eye to right eye is a piece of cake (rt hand shooter).  When the rifle stops moving my eyes switch pretty much automatically.

The problem I am having now is getting from my right eye back to the unmagnified view in my left eye when I start scanning again.  Right now I basically have to blink to sort of reset my eyes.  Hopefully, in time I will be able to transition back to the unmagnified view easier.

well, I've just acquired a TA01 that has seen years of actual SWAT use and I think as long as there is sunlight outside, BAC can be used with this non-lit ACOG.  I would lean more towards the BAC being used for non-lite reticles as opposed to lit reticles.  After a little bit of fiddling I think that a bright reticle would distract your dominant eye while scanning with your weak eye out to a distance.  Like this, my weak eye is able to use all of my brain power (which isn't much...) and not have to worry about what my right eye is trying to communicate.  The right eye gets to sleep.  As long as I've got the cheek weld, my right eye will be ready to take over as soon as I stop and the image is no longer a blur.

Maybe the BAC is for when you don't have a good cheeweld and you can find that donut quickly?  There is still a certain eye relief on all ACOGs so I doubt that is it.  

Quoted: BAC can be used with this non-lit ACOG.  I would lean more towards the BAC being used for non-lite reticles as opposed to lit reticles

That's interesting, as Trijicon says that only the fiber optic ACOGs have BAC.

True. But I was able to get a BAC like effect with my TA01 as well...

Yep, I also don't understand the misinformation in their marketing.   BAC is a technique, not something a scope comes "equipped with".    You can use BAC on just about any scope, although the majority will be difficult to do so with.    
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Well it's something I thought I would be missing out on but it's not.  I'm happy.  

Quoted: BAC will work with any magnified optic, the illumination just makes it about a gazillion times easier. For those of you who dont know, a gazillion comes between a katrillion and a bazillion.

Yup.