...would the cabin crew have activated one of the ELTs especially if they found the biz class sat phones were not functioning?
Having been cabin crew for 10 years with a few different carriers (Asia / Pacific) the use of portable ELT was never taught in initial nor recurrent training as an "onboard" device. Before I read this post it never crossed my mind to use it in flight. We had extensive training about setting the ELT at a high point on land (survival scenario) or its use in water, but I have never contemplated the use on-board an aircraft.
I am not sure that a crew member on MH370 would have thought of that either given the varying scenarios.
I'm sure that given the outcome of the investigation there will be mandated changes for not only tech crew but also cabin crew too.
Cheers for the insight. Might have to incorporate that into a briefing!