-Ralph-

There is actually a situation with an argument specifically against using indicators.

When you are crossing over a major road, by turning left onto it, then turning immediately right, with a car waiting behind you. Where you indicate for the first left turn and move off, the driver behind follows you when you move, whilst looking to the right hand side, up the road towards oncoming traffic and accelerating away. You then indicate right and slow to turn across oncoming traffic for the second turn as the driver behind runs straight into the back of you. He thought you were going left, expected you to be long gone, and didn't anticipate that you may turn right immediately afterwards.

In that situation you are best not indicating at all and leaving the driver behind guessing as to what you are about to do next. The reason he runs into the back of you is because he has seen your left indicator, therefore he thinks he knows where you are going.