>make sure you do it at night. when she sees you at the window.
> in her moment of shook. (gif related) hide or run, disabear like freaken ninja.
>try not reveal that it was you. give it at least a day.
> her paranoia will be hilarious. maybe she will post it on facebook so its perfect to screen capture that. or even give her a call and pretend you have no idea and get that recorded
>if its possible get it filmed. u can just hold it in front of your dark suit, she wont even notice it because your red tie and wight mask will have a lot of contrast.