Capturing a Port locates it's CV

[Max6]

Yes thats true. But in many cases, you might be alone to try to defend the CV. Why not have the ability to use smoke.
And you can turn it of and off. You can save the CV from the enemy`s CV and SB. 

i mean ON and off.....

[Volron]

+1 to the idea.  As some mentioned, at the very least it should put a little "CV" pin in the sector it was in at the time of port capture.  This cv pin will disappear after XX minutes at which point, you'll have to hunt it down the good ole fashioned way...