0.o
If you earn the badge on ReallySuperDuperMan, and then it magically pops up on SlightlySuperDuperMan and KindaSuperDuperMan... Then yes, it is free (or at least sharply discounted) because you put in one third of the work it previously took to earn the badge on three characters. In that instance, getting two badges for zero effort on that character, there's no possible way to claim that you "worked for all your badges".
With the exception of vet badges, on Live you started from scratch every time you started a new alt. And that's pretty much what we're doing now - starting a bunch of alts (admittedly after a gap of some years). Effectively, nothing has changed in that respect.