Sounds liek it ought to be fairly easy to prove that it was an oversight on the part of the clerk and that there was no intention to break the law.
Both of the hosts have tried to contact home depot to get their side of the story but they have not responded, and appear intent on pursuing the matter.
Too bad for Home Depot their biggest competitor menards is just about a mile away - it won't make it hard on their customers to go to another store. And Lowe's is starting to build stores in milwaukee as well. Apparently HD likes shooting itself in the foot.
Congratulations! You've just won the lottery.
Find the best ambulance chasing lawyer you can find and nail Home Depot with a million dollar lawsuit. If the facts are as presented here, you should have no trouble whatsoever walking away with a six figure settlement.
If he goes to court he'll be found not-guilty. It is the "intention" to steal that will get you found guilty. He had no intent to steal the saw blade.