actually, that's a pretty advanced questiond

Client-server programming is a little bit more complex than
pier-pier. The purpose behind CS is control. If this control is
not needed, than yes, any data the server gets (whether memblock,
string, mesh ...) will need to be re-transmitted to all users (user-0). C-S is good if the server handles all AI and other things, while clients may come and go at will during a game.
In DBC, strings are not sent with guaranteed delivery, like memblocks can be. I think the answer is YES ... although I'm not sure exactly the question .. Since all data sent to the server is NOT sent right away, the host must resend the data, IF the clients need the data.
Example:
Player 1 buys a loaf of bread in a village ...
a message is sent to the server ...
the server updates the database ...
no other data is sent to any clients ...
Example 2:
player 1 wants to buy bread from Player 2
sends message to server ...
server sends message to player 2
player 2 says no
sends message to server
server sends message to player 1 (NO)
Example 3:
player 1 kills a peasant
message send to server
server updates database
server scans for nearby players
(Player 2,4,6 are nearby)
server sends message to player 2,4,6 ...
Player 3 and 5 do not get any messages