As another road user this is the one thing that p****s me off more than anything. I think it should carry a 3 pointer and fine.
If I'm on my bike the chances are I will follow you and point out that you have something stuck on the corner of your car.
I too am amazed at the laziness or incompitance (no other excuse possible) of many drivers when it comes to using the indicators.
There are an increasing number who clearly have no idea when to use them even when they can be bothered - particularly on roundabouts.