As a load planner with experience on 757 types, I see this definitely as a non-event. As for the passenger shock at being used as "human ballast", they'd be amazed at how common this is depending on payloads, regardless of airlines. Only difference is that this is usually done with cabin limitation on the check-in system, with passengers blissfully unaware
I'm pretty sure an A321 in this same situation (unusable aft hold) would have had to leave all luggage behind, even with all passengers seated at the rear..
The main problem here seems to be the way in which this was communicated to the passengers, apparently verbally and AFTER boarding the plane. That must have been unnerving, especially if the crew were not English native speakers. Add to this the fact that is was a sub charter operated by a little known foreign airline, and you can be sure that a surge of "Brit-on-holiday-mass-hysteria" was a predictable outcome.
But I find it hard to understand why some people just can't seem to realize when they are talking to a qualified airline pilot who, just like them, does not wish to end up a burning hole in the ground due to an explosive decompression or an out-of-trim aircraft. Or is the Daily Mail front page just too tempting...?
Cheers