Getting a IR shirt sounds nice, but some warning about those who aeroplane. Happens to a kind guy who held a non-profit mass sales last time and the CS shirt as well. I am not trying to be a wet blanket, but few problem can arise
1. People who order, but decided to cancel order or aeroplane in short. (Worst if the payment is made to the shirt printing shop already)
2. People who expected to be treated differently like king because they think only they buy the shirt.
3. You decided to prevent aeroplane by asking for payment first, but people are so busy that they can only collect the shirt 3 years later and expect you to hold on to their shirt for 3 years and above.