Greetings,
In Alliance, we do not use bows with strings that fire projectiles. Instead we use boffer bows and throw blow packets by hand to represent "fired arrows". This allows people to block using their bows without tangling their opponent's weapon or damaging their bow. It also removes the safety issue behind boffer firing bows. I would encourage you to check out the rulebook for more information on archery in Alliance.
It's also worth noting that because bows are used to block boffer weapons in Alliance, the padding required on our LARP bows keeps the archer from damaging weapons belonging to other people.