How often do pro players allow enemy wards to stay standing even if they know where they are?

One thing I always hate is getting caught by a ward while trying to set up a gank. You've been spotted, the gank's pretty much over before it begins, etc.

I have to wonder how much the pro players actually care about whether or not a path is clear of vision before they attack. I know they won't attack into a warded area (most of the time) early on, but when it starts becoming the team fight stage, do players simply not use stuff like Sweepers and don't give a sh!t about whether or not the enemy sees them?

I'm oversimplifying, I know, but I see very low usage percentages on Sweeping Lens for players at Platinum or higher.