If you've never interacted with them, reply. I always do. But judge them on how the conversation continues. If they ghost you after promising X, Y, Z, then I

If you've never interacted with them, reply. I always do. But judge them on how the conversation continues. If they ghost you after promising X, Y, Z, then I don't interact with them again. They aren't reliable. "In successful case, you'll interact with them for a new job and never hear back again (they got you a dream job)." Clearly if they landed you your dream job they didn't ghost you in the middle of the process, right? They must have followed through? Communicated professionally?