Not much financial return. The question left unanswered is, has illegal downloading been reduced? And facts are left out - is that collected, or judgements? If the judgements are higher than that, and I suspect they are, the amount eventually collected, and the theives lives ruined, could be much more.
http://recordingindustryvspeople.blo...s-lawyers.html
"So all in all, for a 3 year period, they spent around $64,000,000 in legal and investigative expenses to recover around $1,361,000."