I think people should be able to OC without being bothered by the police.
However, given the O.P.s specific fear... a crazy relative showing up suddenly and doing harm to his family... how does OC help? It would just let the crazy guy see you are armed, so he could come up with a better plan (sitting in a truck, down the street, with a rifle, your OC pistol won't help much then)
Why give up the element of surprise? How does it help in this situation?
Also, I hope you've pointed out that your wife could benefit from a permit too. I understand if she still won't carry. Many of us are in that situation