FFXIV Does, as we all know, lack some tutorials for new players, although this is, as we also know, being taken care of. It's basically the same thing with the GC enlistment. I think it would be a good idea to add WHY one should think thoroughly about which GC to choose when given the warning. I doubt it will take any immersion away from the player if a small popup window explains that some content will be limited to the specific GCs, in example. Though correct me i this is already there, I can't remember it, but it's been a while since I enlisted, so my mind might be failing me.

But of course, it is perfectly possible that a player knew well what s/he was doing when choosing a GC, and changing taste down the road. In which one should be able to change, but not just like that. If choosing a GC is a big choice, so should changing it be. Let there be a quest for it, preferably a long one, like when enlisting. That might keep players from turning their cape with the wind, yet still making it possible to change for those who truly wish to.