Thought I’d put a link out there for your toy.
http://www.thejammerstore.com/handheld-gps-jammer-gj02-p-152.html?zenid=3r43omtu4tcvsbuvvmtck8tfd6
I’ve seen these, and even though they block incoming signals, or “pings” for lack of a better term, are you certain that they block outgoing signals???
Sure, they stop your Tom Tom and other vehicle devices from receiving, but do they stop the outgoing “handshake” signals???
And once you are outside the “bubble”, obviously, unless you have unpowered any device you have on you, you’ll sing like a canary once outside that “bubble”...
So you can get one of these devices, but you need to understand the complete situation, and do the things to keep you off the radar outside the “protection” envelope they claim to provide...
Just throwing this out there for general consumption...