The sister is the one who invited her over. Just might be a set up.
That crossed my mind, also. Then again, it could be the neighbors, having seen her there at times, who decided to get a WBBM cameraman involved. Either way, it seems there may be more to it than simple stupidity.
But the idea of the sister inviting her over to the husband's house is really intriguing. Heck, maybe she was in cahoots with the neighbors.