Looks like she isn't above the In-law stereotype.

What would she want that for? Sounds a bit stalkerish

Draw the line there. She has no reason to be doing that & you need to have a sit down talk with her about your privacy.

What a creative way to use technology.

That's when you walk over there and ask her what the hell she's doing.

I feel like parents are far too overly protective of their children... To the point of GPS tracking their spouse.

Tell your spouse... Maybe he/she doesn't know she's stalking you... Hopefully you can find a way to cut that psycho off!

Does your spouse know about her behavior? They might understand. Sounds like something all of you need to sit down and talk about.

Set up a few afternoon rendevous' at local hotels with your husband. If she is not following you, she won't know you are with him and will end up showing her true colors when she "breaks the news" to her son.