The security services bugged the HQ of the Communist Party of Great Britain (because the UK doesn't have a bill of rights it's legal to be a commie there). The members found the bug and destroyed it. They were then prosecuted (succesfully) for destroying government property - even though the government denied planting the bug, and in those days even denied the existence of the security services.

Their case was that the defendants believed it was government property and therefore their intent was to destroy government property.

So if you have a reason to be tracked by the police then it would be a crime to destroy it. But if you have no reason to believe you have done anything wrong then it's more reasonable to believe it's a terrorist bomb and you should call the FBI/DHS/Army etc

Back when I worked for a defense company our cars were checked with mirrors on sticks everytime we went to work, we had special police numbers to call if we ever saw any suspicious activity around our cars or received a suspicious package at home.

Although they weren't very understanding when I was away on a trip and my wife opened a package containing a microcontroller I ordered - and started an alert!