I'm not 100% certain, but I don't think it's possible for someone to crash into another player and cause them damage in AH.
I don't know the details of how collisions are tracked in AH, but if I'm not mistaken the reality of netlag means that it's next to impossible to 'crash into someone' and have that do anything to them.
You may see them crash into you on your machine, and then you will die, however that requires you to fly into them, not them into you. If they crash into you on their machine, they will die, but the reality of netlag means that you probably saw them a hundred yards or so away and then they just exploded for some strange reason.
In other words, if they are HO'ing you, and they run into you and you die, it is your fault, even if they 'started' it, and you are trying to avoid the HO. You need to be a bit quicker on the evasives, and get your own nose off of them.