Should I have stopped them?

OK I am officially a grown-up, yesterday the girls where pulling the heads off the dandelions that are in the "puff" ball state and blowing them. I panicked, I wanted to scream, "oh my gosh stop doing that, don't you know if you blow those things they will create more of those ugly little flowers?" I know that I did this as a kid even now I would love to pluck them and blow the little feathers off but the "grown-up" in me knows that if I do this then what little grass that is still in my yard will turn into dandelions.
Just so you know I didn't yell at my girls I turned and went back into the house, kids should be kids they should be allowed to blow the stupid flowers apart, I did. Did my parents and grandparents go back into the house when I did that?