Petey -
If you practice basketball at school with a leather bastetball, and your team shows up at some school to play - and they use rubber basketballs - can you play them competitively? Can you play flag football with a leather ball and a nerf? If you always practice with green Wilson tennis balls... and you show up to play someone who brings orange Penn balls... can you still play?
As humans we can adapt very easily and quickly. I don't see this as being a huge problem for human players (yes, on planet Utopia, all human players would practice with the right ball... but they will deal... and still do well).
Aidan