I recently found an all black steotoda that I wasn't quite sure wasn't a widow without red. I live in Bothell and "knew" it couldn't be a lepto, so I googled black widow in western washington, I found out there are a few introduced small established populations in this county, but I still believe what I have is a Steatoda sp. most likely a S. borealis. Also, studies claim their bites are nearly as painful as a widow bite, with skin necrosis occurring in a few australian bites, but not associated to the neurological dangers that widow bites can have, so tell your sister to be careful if she tries to catch it.

Here's a link to another local person who photographs spiders that he has ID'd by the Arachnologist at the Burke Museum.
http://www.ivory.org/spiders/index.html.