I wouldnt depend on the cop not showing TBH mate. not worth the risk.
Also, do not piss off the cops by jamming their guns or they might pull you over and nail you for it or something else they can think of at the time.
JTG (jam to gun) is a dodgy practice and it also causes problems for other people that use jammers also when they are made illegal.
Just slow to PSL and shut it off and you will be fine and nobody will be the wiser
