Rumor has it that Norwegian will not pay compensation after EU261 in these cases, on the grounds that the tech errors has been out of their control and could not been anticipated. Stranded passenger have received accommodation and meal vouchers, which is sufficient according to the airline.

An anecdote on the "low cost" profile of Norwegian, I'm off to BKK in early December, returning in mid-January. Norwegian's quote was ~£1000/rtn which I don't consider low cost at all. QR had flights on the same for ~£450 in Y, and ~£1350 in C.