Should you say anything to someone you don't know if you see them in a shirt you also have?
Today after school, I saw another parent wearing a Woot.com tshirt, and I didn't say anything, because walking up to him and saying "Woot!!" seemed strange.
It was kind of neat to spot a Woot shirt "in the wild" and not just in the confines of a comic book convention.
You could just say "Hey, cool shirt!"
Of course, if it is one you have, it might be kinda awkward if they see you wearing it later.
Yeah, not sure exactly what to say in that case, "Woot!" might be odd, but if it is a woot shirt, then hopefully it is the sort of odd they would appreciate?