Thomas Shey
Legend
I don't recall ever playing a game which has mechanics to trigger flashbacks, but I have occasionally (very rarely) used flashbacks while GMing. I think it can easily be a tad awkward from player perspective though. At least to me it has potential to cause an immersion clitch. "So I knew all that the whole time?" "That traumatic thing actually happened chronologically just before the first part of the session where we all were behaving like we had no care in the world?"
It is, but I can't help but think other than avoiding the whole concept (which is important to certain kinds of genres and stories), you only really have two options: flashbacks or a really bland "preparation" currency that serves the same purpose without explaining itself.