FWIW, I was a pax on one of these last Thursday (13/05) - I can't believe they got 15 pax on board! There were about 8 of us (and loads of luggage) and things were pretty tight (admittedly, we were fat westerners, not skinny locals).
Far be it from me as a totally unqualified pax to pre-judge the cause of this accident, but it seems to me IHD has a point.
Glad everyone is safe and hope the injured lady makes a speedy recovery - it must have been pretty frightening.