A-ha, but this most decidedly not formal writing! UNO REVERSE CARD.
But on a more serious note, I did intend it as a sort of question because I’m not 100% sure, because the rules for quote use might well be different in English than my native language. I actually also don’t know the rule for question mark usage in English; is it generally considered a crime against orthography to plonk a question mark on something that’s a statement, or is it valid in some cases?