Yes, there is such a thing as pie thrower's karma. And you should know about it before you take this up as a sport.
True Story: Once a random collection of four friends showed up at one of my birthday gatherings with a large pink box wrapped in a pretty bow. They told me it was a surprise, and to close my eyes. Split second later I realized what they all had in common. They each had separately been on the receiving end of one of my pie throws over the years. Oops.
So I quickly opened my eyes just as their communal pie was hurling towards my face - with no time to dodge.
I may have inhaled a little whipped cream that day due to four determined hands making sure it covered my face. But hey. That's karma.