How to Get a Cat Down from a Tree

Some background - A little while ago we got a kitten.  Her name is Callie (or Kalamazoo, depending on if she is in trouble or not) and she's now about 6 months old.  She's been spending time outside during the day lately when we're home and recently discovered our large elm tree in the front yard.  The lowest branch on the tree is about 15 feet off the ground and apparently it made Brady nervous for her to be up in the tree.  So, he decided she needed to come down.  I walked  around the corner of the house to see Brady with a football in his hand and his arm cocked back ready to throw it up into the tree.  I initially didn't realize Callie was in the tree, so he got a throw off before I could stop him.  As it bounced off a branch, I looked over to see Brady's friend standing opposite of him with his arms held out ready to catch the cat.  It took me several minutes to convince the boys that:

1.  Knocking the cat our of the tree with a football is a terrible idea.  In fact, I think I used the phrase "terrible idea" more than once talking to them.

2.  If they did succeed in knocking her out of the tree, she could be really hurt, either from the football hitting her, or from the fall.

3.  No matter how hard they try, they will not be able to catch a falling cat in their arms.

4.  Cats come down out of trees on their own if you leave them alone.

The whole time that I am trying to explain all of this to the boys, Brady is standing there holding the football, ready to throw it again; his friend is standing there with his arms out saying, "I can catch her, I really can"; both boys are looking at me with doubtful looks on their faces that say "I hear what you're saying, but I really think the football method is a better idea", and Callie is climbing higher and higher into the tree.  Finally, I convince the boys to move on and shortly after, Callie, deciding the aerial assault is over, climbed back down the tree.  Crisis averted.