I agree with many of the people that say LARP arrows are safe. I've played with them for years, and no real safety issues that are worse than a packet to the eye. They are very safe now. The big issue like Lurin said is damage output. It's hard to output enough arrows to keep up with packet throwing.
We tried to order one of these in to test them, but I don't think it ever arrived - http://www.b3is.com/shop/Deluxe-Padded-B3-Packet-Bow-p81978175