During the recent tsunami alert around the Pacific as a result of the Chile earthquake, many people did not heed the warnings and actually headed to beaches to watch. 

Here in New Zealand, some of those who did this reportedly said that the expected height of the tsunami was only a few centimetres, which they could not see as being dangerous to them.  They added that they would have run if they had seen anything more dangerous than that coming.  

Well, to show how foolish that response was, here is a security camera video shot in American Samoa last year.  The tsunami in this video is only a foot or so deep, but despite this low height the waters pick up and toss round vehicles like Matchbox toys, leaving them smashed up in a pile, By the time someone realised that such a low 'wave' was in fact a fast-moving and dangerous tsunami surge with the full inertia of the ocean behind it, I defy them to have managed to run away in time.  

The video is quite long, and the tsunami only comes in right at the end, so you might wish to scroll through (though seeing it in full emphasises the sudden contrast from a peaceful commonplace scene to violent anarchy): 

http://www.youtube.com/watch?v=Qi9gApr7x68