can I crash on your floor tonight ?

See this 09/27/2010 message from a resident on the unit block of R Street NW:

We live at First and R NW. This past week Thursday night, my housemate was arriving home around 1:30 a.m. A young (late 20s), white woman with dark hair walked up on the stoop as my housemate was locking up her bike and asked if she could crash on our floor for the night, that something had happened downtown and she just wanted to get inside, etc. My housemate told her she couldn`t let her in, went inside the house and the woman presumably left.

My housemate`s friend who lives at First and O NW experienced the same thing with a young black man who approached him making similar claims a few months ago. I wonder whether this is a tactic that is being used to attempt to get inside houses to then steal from the house, or whether there`s some other explanation.

Anyway, thought it would be worth sharing to see if anyone else has had similar experiences or any insight.