I have seen quite similar question asked less than a week ago (in the dedicated thread -
Investigation into the "Mysterious Stranger" )
Yes, they are still in game - recently I've received 59 of them
However I do know at least one method to "break them" (i.e efficiently block any subsequent tip off mission assignment) in the case of any particular commander.
And where there is one method there - supposedly - could be others.
If you do receive them in quantities (>50 over two weeks) then I potentially could be interested in associated locations=)