Doesn't everyone stick half a foot on a zebra? Stopping is not farking optional, not that you'd know it from how motorists behave.
But you have to concede that there is a bit of give and take and certain things help. For example, if you are stationary, in a busy area waiting by a zebra crossing, there are a number of things that can happen.
- The motorist just won't notice you because you are not moving.
- The motorist won't stop as they are trying to work out whether you intend to cross or not, or whether you are just waiting for someone.
By moving forward and putting a foot on the edge of the crossing, looking to see if the cars are stopping, your body language indicates to the driver that you are waiting to cross, so they are more likely to see you and stop. However, its possible that they see you too late to be able to stop safely, or they are just a**holes.
So yes - in principle drivers should always stop at a Zebra crossing, however in the real world this is not a given for many reasons, some of which are outlined above. Thus, as pedestrians or cyclists we can give signals that help facilitate the crossing transaction - but caution should still be exercised (in my view).