Jimjetter, Are you travelling on concessions? If so, watch them at MIA on the return sector.
In my experience, BA staff travel out of MIA is a joke, they do not respect the onboard priority and seem to onload as they see fit.
If you have a m8 that works for BA, you're best to ask him/her for a hotline ticket, that is confirmed. Also get them to check the loads and your onload priority for the return, so you can let the check in staff know at MIA that you know when you should be boarded.
Have a great time
