The Pelican crossing problem is one that always gives me ethical problems while walking. If I arrive at a crossing and there's no visible gap in the traffic, I'll press the button in the hope that this will allow me to cross the road. It seems to me that this must be ethically OK, since if people weren't allowed to press the buttons the crossing wouldn't be very useful. Once I've pressed the button, the lights will change whatever I do, so the traffic hold-up (if any) is now inevitable. Given that, it's hard to see why crossing in a gap in the traffic before the lights change is wrong. Waiting for the lights won't help anyone else, and will hold me up, but somehow it still feels like the right thing to do.

Of course, if I'm going somewhere for work I'll always wait for the lights -- to do otherwise would upset the safety office.