I'd get one of these "security pens" from Office Depot, for $4.99; and replace the ink with a purple one. https://www.officedepot.com/a/products/196063/FORAY-Security-Counter-Pen-Medium-Point/;jsessionid=0000zuGLJFZSldVFQ85KXz2Vwqg:17h4h7cou

Let her try to steal that.

The 45 year old sounds like she needs genuine psychiatric help.

The creeper too.

Could you bring in your own little microwave, and hide it somewhere?