We have purchased a supply. People love to see pictures of where you are from. Make sure they are tagged. Also luggage space in the vans will be very tight. Some helpful hints .
Backpacks are easier to carry through the airport and are useful at the worksite and sightseeing.
Space in the vans we rent in San Diego will be very tight for everyone's gear plus people. You can squish a duffel bag into a much smaller area than a suitcase. A money belt is a good idea. You won't loose it during the night and it is cooler than a sleeping bag. Some are thinking about bringing the sheet and buying blankets in Tijuana to use and then bring home.