Very low, I was playing draft yesterday and everybody was doing it
I was thinking that, surely they won't ban everyone cause then there would be nobody left to play the game

What is the likelihood of getting banned for doing the no lose draft/seasons glitch?

you did it wrong then, its still working for me. i got screamer douglas costa in a pack from "winning" the draft
I'd done everything the exact same as before though I don't understand?

Played 4 drafts today's winning the first 2 but the second 2 I don't the glitch and it didn't work? Tried in on seasons and yes it still worked though