What if you changed the BOX graphics for box targeting for Soldiers and Vehicles so when they do get a box target it does not show as the graphics has been changed to a transparent block?
This could be make a option for servers, once turned on OFP could tell all clients to change that specific part of the game, simple graphics switch.
This be a nice feature for a future patch, basicly box targeting is form of cheating, althought its a feature in the game its a major drag for MP since you can lock on and target and see objects from unlimited distance away, you don't even need to see them just aim for the box and boom you win..
This is just a thought, hope its possible, only time will tell.
PS. I wanted to post this on the BIS forums but it seems they are locked for some reason or something, if ne1 has access to them feel free to post this there as I can't.