I the example i've given, it is not possible to download directly to the unit/card anything other that the lower 49 image. Of course, the entire NA is dl'ed as a gmap to the PC if that option is chosen as i said. I think Garmin is having a 'two-way bet' on this. On one hand they clearly say [conditionally: 'unless otherwise stated'] that you are going to get only your OEM content updated:

Unless otherwise stated, the updates you receive under the subscription will be updates to the same geographic area included with your Garmin product when originally purchased.
(That's a legal statement only).

On the other hand, they have charged for a full subscription to NA. Trade Practice laws in many countries prohibit a supplier from charging for goods or services that won't be delivered, including partially not delivered. So i think the Garmin lawyers are smart enough to say to the marketing department 'Let them download the entire area we charged for, but only to their computer. If anybody complains, we can say that they are in fact entitled to AL/CA & MX and can load those areas separately via BaseCamp/MapInstall to their unit memory and/or media card along with the required codes'. That's the reason, i am absolutely sure, why you can in fact load the additional areas with gma & unl separately as another step altogether after dl'ing the US only image. Hence the 'get-out-of-jail-free-card' you pointed out "Unless otherwise stated" and the other related statement you quoted:

nüMaps Lifetime gives you full access to the entire map coverage; however, some devices have limited memory and may not load the full North America map (nüMaps Lifetime also will update City Navigator® NT maps on your computer
(That's both a legal statement about entitlement and a forewarning regarding possible limited physical memory)
So we are actually agreeing, not disagreeing Kanopus. Maybe looking at things from different angles is all.

I haven't tried but i'm sure it is also entirely possible to dl only the gmap folder and then send the entire NA or just CA as you suggested to the [OEM lower49] unit as the new detail map image, but then how do you easily then get [direct from Garmin] the JCV and in the case of entire NA if it's got Voice Recognition and for that matter 3D capability also get those files too without a useless downloading of the OEM-only img direct to the unit? Is there a trick i don't know of to do that?