I just flew from England to Belize via Dallas, on American Airlines. My two checked bags didn't change during the stopover, one being a little over 50lb, the other closer to 70lb (but still under).
No comment was made when I checked in in England. When I re-checked in Dallas, however, I was told that all bags between 50lb and 70lb are surcharged, and furthermore that this has been AA practice for several years. I was forcibly parted from US$100.
I have flown between Belize and the UK many times over the past few years and I have never heard of this before. I checked with three American friends who fly internationally several times a year with various airlines and they had also never experienced this surcharge. Is this just another scam perpetrated by AA or is there some foundation for it? What about other airlines?