I just read an article about a man who booby-trapped cardboard boxes on his doorstep because porch pirates had been stealing his deliveries for months. He had a few interesting contraptions, but the first plan was to offer his cat's ripe litter box holdings to the next thief, which worked fine, but then the discarded box was found by a neighbor and returned to him. Not cool. Come up with some brilliant booby-traps, and let's see who gets the most "likes" for creativity and description. Multiple ideas are fine. Add, if you want, possible failures and fail-safes. How are you going to teach these thieves a lesson? Paint a picture of your porch if necessary; and an extra challenge for Sushishi, Sadhill, and PrettyScaries: try to keep them alive... you know... at least for a little while.