Shocking! :(

One day one of those youths will become a great climber (see: Paul Pritchard in Deep Play)

So is that enough to condone people lobbing crap at people?

Chill out, I didn't read any condoning in Guy's post, simply him musing on a bit of history. I've been showered with glass and debris when climbing at Black Rocks myself. It's well known to be a hangout for local youths with nowhere else to go, and yes, knowing no better, they tend to lob empty bottles off the top. Fortunately in my interaction, my friendly approach paid dividends and they realised they had put me in danger, appreciated that I hadn't gone ballistic at them, tidied up the rest of their mess with my assistance and left having learnt something. Could easily have gone another way if they'd wanted it to, c'est la vie.