NigelOnDraft makes some sensible points. Now I've never seen a Hot Start (never heard of them before this thread), but as a mere fare paying punter I think that if I did - and especially if it was one of those 20 foot dragon types NOD mentions - then there would be a certain amount of trouser clenching going on.
I'm not sure I'd be doing my "I'm a a passenger, get me out of here!" thing though I may mention it to the CC. So are they briefed/knowledgable on these things to mop fevered brows? And is there a given set of circumstances whereby you may well be expecting a burp as you start up and would it make sense for the drivers to make a PA on the matter? Or would that be more likely to get the unwashed masses in a flap?
I shall obviously now spend my time begging for slightly rear-of-wing seats when flying in order to witness this phenomenon and then be able to show off my vast knowledge of all things aviation to assuage my fellow travellers! Well done PPRuNe ...
Duncan