One of the things that brings a smile to my face more than almost anything else is when I'm getting pounded and a friendly destroyer lays down his smoke to cover me. I always thank him and throws a 'plays well' at him. Seriously, if you do this for a fellow green, you da man. If you are that kind of player, this thread is not about you.
One of the things that infuriates me more than almost anything else is when a friendly destroyer lays down smoke to cover his team, and at the same time obscures the red team ships, making them disappear too. Even worse is when he does this the moment he drives into a cap zone, while still unspotted.
So, if you lay smoke for your team, please make sure the red boats remain spotted so we can have something to shoot at. One of the primary roles for destroyers is to light up the big bad red boats so the green ones have targets. Giving them a helping hand by laying your smoke screen so we can't see them is counter to that mission statement. Especially if you then sit in your own smoke and camp there, while they remain unspotted. That's just giving the red team a free smoke screen.
Please, if you lay down a smoke screen either ensure that someone else is still spotting the red ships, or drive outside of your own smoke to spot the enemy team.
Ofcourse, this all goes out the window if you're being shot at and have to lay smoke to G the F O or be sunk. Live to spot another day rather than give your ship away.