Sometimes those “smart” houses aren’t so smart. Apple fan Marcus, a homeowner in Illinois, decided to outfit his home with every gadget available that claimed to be compatible with Apple HomeKit. His home had Hud LED lightbulbs, Ecobee thermostats with sensors through the home and an August Smart Lock. He could control the lighting, temperature and locks in his house with an app on his iPad.

Marcus enjoyed being able to walk up to his front door and having it unlock for him when his phone got within a certain range. He could let his dog walker in when he was not at home. When he was home, he could enlist his trusty assistant Siri to help him by giving commands like, “Hey Siri, dim the lights.”

Excited by these new fun features, (and thousands of dollars poorer), he invited his neighbor Mike to come over and check it out.

The Apple HomeKit is great, if you take certain precautions.

Then one morning as Marcus was leaving, Mike showed up and asked if he could borrow some flour. Marcus started to get out of the car to open the front door for him, when Mike said, “I’ll let myself in.” He walked right up to the door, and called out, “Hey Siri, unlock the front door.” The door unlocked.

So, what happened? His neighbor had figured out that if he called to Siri loudly enough through the door, she would hear him through the iPad Pro sitting inside and unlock the door. It worked. Marcus has since removed the August Smart Lock.

The story reminded me of when I installed my own security system at a company I was running. We were losing a lot of merchandise to theft through the back door of the warehouse. I needed a solution fast, so I put a “camera” next to each of the 10 doors. Actually, I just drilled a hole in the wall and fed a wire through it with a battery-operated red light right next to it. The camera and the wire didn’t go anywhere—and neither did my merchandise after that.

The camera functioned as a psychological theft deterrent that scared those who considered stealing. After reducing shrinkage, I had the money to upgrade the security and improve the inventory tag system.

My method worked for me in that particular case, but I know it wouldn’t have taken long for the thieves to catch on to my fake camera system. So, I don’t recommend it. But I can’t recommend the more expensive smart home system, either.