ok so
if I use "createvehicle" to create an object on one client and that one client runs a script that tells the object to "say" a sound--all the other clients will hear it wont they?
Answer is yes.
No, the answer to "If I use..." is "no". Look what Dinger said - he answered yes to the statement 'Do I need to get all the client to tell the object to "say" the sound?'
Again: if you want something somewhere (be it local to or created on a server or on a client, no difference) to
say a sound, you need to execute the
say command on all client machines for all to be able to hear it.
The same thing goes for
drop and many other visual/audible things in OFP. (
addMagazineCargo is a nonvisual one of the same type, btw)
Then, as to confuse you even more ;D, some commands should
only ever be executed where a unit is local.
Action is one of them,
setDammage another. Ever experienced a (scripted) ejection script that kills almost everyone by having them plunge to their deaths? Ever had AI:s in your group not get out of a helo after a insertion script? No, its not "buggy OFP" or "lag". Some dumbo just did
unit Action ["eject", vehicle] on each and every machine. Don't do that. Only where
unit is local.