Considering it took off from LAX it started out over the Pacific. In order to dump fuel over the Atlantice, it would have to cross the US first.
The Miami incident was an emergency landing. I not sure if they got down to the recommended maximum landing weight or not. They didn't have much choice, because the engines weren't going to last very long.
Considering the flight path was going to be over land for the first few hours anyway, why dump fuel when it could be burned off enroute to an alternate destination where the passengers could be switched to another plane? The other three engines seemed to be working fine. It would seem to me that flying over the continental US with three engines working would not be very risky considering the number of airports available for diversion if necessary.
Yes the Miami incident with Eastern Airlines was a dire emergency and it may have been a really hard, over-weight landing (but of course better than crashing from total engine failure).
Due to some changes in rules in Britain, the Airline is now responsible to pay compensation to passengers at forced layovers.
This is all about the bottom line and not the first time it has happened since the new rules were announced apparently.
The FAA wants them to change these rules or mandate compliance to U.S safety standards.
I don't blame them a bit.