You should know that there are a large number of tutorials online for ways to make a handheld EMP (electromagnetic pulse). They will disrupt electronic devices in your vicinity and would be very useful if masked men approach you and try to photograph you with a potentially illegal biometric collection application. If made correctly they are harmless to people, and if made incorrectly they are most likely harmful to the operator. It is a non-violent defense device.
ICE is literally doing this right now in the US.
Ah, well, they don’t need to worry about being caught or identified, they can just stop you in the street. I thought you were referring to scammers or something.