I am wondering the same thing. We don't want people to bring gifts to Mexico, like you said them being there is enough, but we are also having an AHR and two bridal showers for me, and we wanted to register for that..and if anyone wanted to get us a wedding gift that isn't coming to Mexico;). I have seen people put something like "your presence is a gift enough, however if you feel inclined to congratulate us with a gift, we have provided the following registries for your convenience". This is a hard one!