Don't mess up/risk your own computer just your friends... You must have trusting friends. lol
Well, that depends. What if they're not friends but "friends?"
LOL fair enough, fair enough
That's not really different from piping to shell, risk-wise.
Yes it is. If I'm piping to a shell as an unprivileged user, there needs to be an additional round of exploits to do nastiness to other than that user.
For those whose security model looks like http://xkcd.com/1200 that's not a big difference; but depending on context it might be.
But your unprivileged user account is going to have all the stuff that matters anyway.
I raised that point with the comic. Frequently that's the case, in which case yes, not much different (though maybe it's less likely to do hardware damage, maybe...). It's not always the case.