Yes, that one. Never trust father gods.
Hm, does the coming-as-a-snake imply Zeus? Or what epiphany does Hades have?
It's a combination of that Zeus has acknowledged Dionysos as his son (which would have been a big thing if he actually wasn't Dionysos' father), and that it's quite typical for Zeus to trick women this way.
Ah, the acknowledgement, did not think of that.
I think it’s more the “son of Zeus and…” line that implies who Dionysus’ father is, rather than the snake
Also, "who is the father?" has better than even odds of having "Zeus" as an answer anyway.