carpe noctum

On my way to school this morning I saw a man at Sydnenham station wearing a t-shirt, not exactly like, but similar to, this one. It shouldn't be that hard to get the accusative case of the third declension right, especially if you're going to print it on a t-shirt. And why would you wear something like that? Haven't that guy's friends told him how silly he looks with a huge grammar mistake printed on his chest in a gothic font?