They probably did not give a Mayday call because the pilot in command did not believe that they were in "grave and imminent danger" so how about we leave that alone, yelling from the sidelines is so easy.
Landing with less than FR, mmm, MOST fuel policies only say how much one must PLAN to land with. Therefore if you land with less than FR it is quite possibly not an offence, merely a cause for reporting and explanation. Before you jump down my throat about this sacred cow, please post a reference to where it says the aircraft MUST land with FR intact.
I think this thread has run it's course in the absence of any new information.