i've been that guy in the form of the ratty old shirt and putting the new shirt on top of the old one, and more.
more?
here:
going to see a band while wearing a band shirt from a more obscure band which the band you're going to see gives a shout out to in one of their most popular song.
example: you go see band y wearing shirt with band z on it. band y has a rather popular song called "[insert name of song here]" in which they say in between choruses "this song goes out to band a, b, c, and z!".
or you go see band z wearing band q's shirt, when band q happens to be the slightly more popular band fronted (or co-fronted, or not fronted at all - maybe he's the drummer) by the frontman of band z's older brother.
or say band z were around for a few years, broke up, and half of them formed band g. then band g broke up, and they reformed band z. you then wear a band g shirt to a band z show. on purpose, of course, because you are sooooo cool and soooooo elitist that you own a band g shirt, even though they only put out one 7-song EP in their entire career.
i voted don't be that guy, but i really don't give a shit.