Well photos are a MUST. My son played travel baseball one season for a pretty unethical coach, we left when we found he had copies of other kids birth certificates that had previously been on the team, he kept them as his "proof" of age for the ringers he would poach. For all I know he may have made copies of my sons birth certificate to hold for future use.
Nassau suffolk football league holds a photo registration night before the season starts, any new kid must show up in person with birth certificate have photo taken. Laminated cards are issued, coach holds them, prior to every game they are inspected and matched to each boy there. With football size is a huge issue for liability when you can have a 80 pound 13 year old in the same league with a boy that weighs as much as 160 pounds.