Originally Posted by
corporate-wage-slave
You are effectively in a seat sold in bulk at a special price for cruise line companies (etc), and some travel agents get hold of unused allocations for general sale. They are highly restricted, low cost and often not open to TPs or Avios. Caveat emptor, methinks.
I think that's a tad harsh. It may be the reality, but booking just a flight through the TA it wouldn't occur to me to ask "Is this some kind of restricted fare that precludes upgrades with Avios?".
I wonder whether the average TA selling these fares would understand the question and be able to answer accurately...?