It's the airline's problem...blaming travel agents, part-way through a trip/flight and making the passengers reponsible for someone else's criminal act is criminal in, and of, itself.
If they (the airline) didn't have the cash/money from the TAs before the flight started, what could have possibly been the excuse, from the TAs, to possibly lead the airline into believing everything would work out before the flight reached its final destination if the airline would let the flight take off?
I say that the airline is responsible for taking the TAs to the woodshed.
The airline is in a much better position to collect than 100s of passengers that #1.) Don't have the lawyering resources that an airline would; and #2.) An airline could ruin a TAs' less-than-worthy reputation much more effectively (and legally) than any passenger could ever dream of.
If I were a judge in this case, I'd order the airline's assets frozen, then disperse the passengers' collections back to each, plus a year's worth of interest, then award them pain/suffering compensation...then I'd have each and every TA involved drawn and quartered.
Too bad on the D&Q. It might persuade others from a life of larceny and whatnot...but then, maybe not...