They are very good for capturing those moments of hooleying down the aforementioned riverbank whilst recklessly endangering the lives of you and all around you!
Please excuse the slowness of my cob, but with his diving boots for feet he had no chance against my friend's "posh" TB/WB
http://www.youtube.com/watch?v=F4FzG5SFsEo
HOW could you suggest such a thing? What about the strain on the poor couch hmm? Hmmm?! It could get an RSI!
Seriously, the levels of irresponsibility on this thread are SHOCKING!
We were only out for an hour and a half, but went on the newly surfaced track, which we had to negotiate a rather busy road to get to. The mare is not frightened of traffic, but can be somewhat frightened of bushes, plastic bags, sheep that aren't the ones she shares the field with, tarmac that is a different colour from the rest of the road, puddles with sunshine on them etc. etc. etc. but we still upped the pace a little And we came home safe and sound. I have never competed for my national team in anything, but in about 40 years of horse ownership I have only twice returned from a ride with an injured horse, both times were with the first horse we owned and both times we splatted on the road (I am sure both incidents were my fault, but I have learnt a lot since then). Over the years I have cantered on tracks, grass verges, through woods, all sorts of places (once or twice involuntarily even on the road! 
). Each to their own and long may we all enjoy ourselves 
)