Normally we would, but the convention in question is GenCon, the largest gaming convention in the United States.
I know that a lot of people are tired of shirts (I know that I have several from companies that ceased to be), but at Gaming convention goers in particular people are more likely to than average to wear T-shirts rather than white dress shirts.
It also means they need to pack less clothing for the trip.
Also, note the success of sites such as StartupSchwag.. People are willing to Pay for random branded T's.
I know that a lot of people are tired of shirts (I know that I have several from companies that ceased to be), but at Gaming convention goers in particular people are more likely to than average to wear T-shirts rather than white dress shirts.
It also means they need to pack less clothing for the trip.
Also, note the success of sites such as StartupSchwag.. People are willing to Pay for random branded T's.