Apologies for accidently using an illegal deck in the second game of the first match
It looks like 3.3 of the rules allows me to go unscathed though (if a match is done and there was no request for a legality check illegal decks wont get punished).
Being a single card off (that didn't win me the game, in fact I didn't draw it) is probably the smallest offense I could come up with, but its still clearly a mistake that had a small chance to change how things went.