The connector can probably be SMD as well, as it wouldn't hold as much stuff anyways. Stickers on shirts might work the first day, but this is a three days event. Supercon can be overwhelming, so taking time to program a name tag might already be too much. There could be some slightly glowing white LEDs instead, like @arturo182 uses in his marker badges that he gave out at chaos camp. But then this badge might need some stacked boards instead. So white silkscreen feels like keeping it simple.