Hey wandering_fred - so interesting thing has happened. AA desk allowed me to book this. I was booking two itineraries both of which included this scenario. They then went different directions for later segments but the transit without stopover in MIA between GIG and BOG is on both.

Today I got notification that one had been priced ready for payment and the other has a routing issue and I need to call. When I called the agent said it was those sectors as you suggested but then I asked why the other booking was OK and she agreed that it was strange - I did say I expected it to be the case but then also stated that the rules allow a second intl/arrival in NA provided it is a transit without stopover and I also mentioned the fact there are no other internal flights within SA (save QR GIG-EZE) so almost pointless including SA in a DONEx in any case but at least this helps if allowed.

The agent spoke to the rates desk and pointed out one had been rated and the rate desk said yep should be ok and they will rate mine as well and come back with pricing in an hour or so.

Yet to be confirmed but if it comes through then I have a couple of questions for the learned:

1) I'm almost certain to need to make date changes to these bookings down the track - am I likely to hit potential grief with that even though AA has accepted it and ticketed it prob outside the rules?
2) Is the only point of having two NA arrivals/departures rule to add some minor flexibility to an XONEX say perhaps for itins originating in SA to allow a few more options/ways of getting out of or back into SA? And perhaps allowing a few additional cities in SA to be added to a routing that are accessible only through the US eg CLO/MDE etc?

If they do start to interpret it that a re-entry to SA is ok in conjunction with a transit without stopover in NA is OK then it def improves the dire lack of OW options in that continent