They sometimes throw this device into boxes so they know when the box has been opened, my guess it might be simple RF to signal to the cops waiting outside, or more likely cellular/gps so they dont have to. No one on DNMs has ever actually had the bad luck of seeing one of these devices but leaked intel from feds has described its function. Lets say your smart about ordering and dont get stuff sent to your house, you collect from your PO box and now you got this package that they cant watch cause you havent been to your PO in a week and they dont have the resources to watch it, this package has this device in it, its in your car and you assume once you move away from the PO its going to pop up on their computers that its moved and now they will come straight to you. You could also try to take your drugs out at the PO, but these things apparently know when the package has opened (trip wire along the walls of it i guess), so that doesnt work.
So what do you do, put your package in a faraday cage, signal is lost, this might trigger it as well, but at least you dont have to leave evidence behind and you can drive away without being traced. Thats the best i can come up with, no way of knowing if you package has this thing in it and if it does you are fucked if they find you with it. Need more info on what this thing is and how we can defeat.
I wonder if slicing it open in the middle would help.