Another way of making your point: it would also make the information about the distribution of n irrelevant, so it's a bad interpretation of the question.
So? There's plenty of problem statements with irrelevant data. Children are also getting taught to determine which is relevant in class.
But also, it's not irrelevant because for two cases the probability stays equal. Calculating the exact chance is still an interesting problem and it could have been dumbed down for twitter only.
In those cases presumably there's not a more interesting question that's consistent with the question and that uses that information. I'd start with the assumption that the tweet isn't a dumb trick question.
