Wow! - Eddy what a deeply worrying response to a not very deeply worrying situation!!
You don't think that linking flybywire's comments to the HELIOS crash is just a little bit tenuous?
One possible alternative scenario runs as follows:[list=1][*]The part of the Cabin in which flybywire was seated was cold[*]The Cabin Crew(s) mishandled the request to warm it up[/list=1]
The management of Cabin Temperatures is always a compromise. The temperature will always vary throughout the cabin, and be influenced by other factors outside the crews' control, such as different pax clothing, medical conditions and fatigue, as well as the proximity to various items such as vents and doors. It is common to receive pax requests for contradictory temperature settings within 2 or 3 rows. A skilled crew member will handle such requests appropriately: A bad crew member won't.
In safety terms, there is no evidence that this situation was safety critical, nor that there was negligence, nor that it was/is "Sickening".
A "Double Ding" is not necessarily a flight deck call: The procedure will vary from airline to airline, some using single or even triple chimes. A call may be answered at a different handset, thus leaving the light illuminated at the station called, even though the call has been answered. I don't know if this was the case or not in this situation, but it is possible.