In SPOTREP #00058 it says under ENGINE:
Added: A new drawingInMap server.cfg parameter to toggle the Line Drawing on Dedicated Servers
However, if one adds drawingInMap = 0; into their server.cfg file line drawing is still available and visible to other players (depending on chat channel selected).
Note: On the BI Wiki the drawingInMap param description says "...(since Arma 3 1.63+)."