Huh, same thing happened to me a few months ago. Scantily clad 18-ish or so girl (from Iowa or some place like that) wanting to sell me magazines and wanting to come in to use my table to do it. She was asking me the same kind of questions. When I said I wasn't interested she said she'd get in trouble from her "supervisor" for not filling her quota, and that she'd been out all day trying, and "look at my sunburn" as she dropped her top part way down a boob to show me. Didn't expose anything completely, but kind of obvious what she was trying to do to get me to let her "use my table".
When she saw I was adamant about not buying, she asked if I could walk her to the front gate because she didn't remember where it was, and again, her "supervisor" would be mad at her if she wasn't out front when he got there (I live in a condo complex and she was referring to the front gate). It's IMPOSSIBLE to be lost in my condo complex. Think of a rectangular room with no obstructions and a door at one end. No way you could not see it.
At that point I figured something funny was REALLY going on (at first I thought she had a novel way of selling sex), and I said okay only because I wanted to see if she had any friends loitering in the parking area. It was around 8PM, so I'd answered the door with a pistol in my back pocket. I told her to hang on a second, walked 10 feet back to where my house key was, and in that time she'd already opened the screen door and was starting to come in. I gave her a "what the hell?" look, and she turned and went outside. She saw me lock the deadbolt, then we walked down my stairs, walked about 50 feet, then she said, "Oh nevermind, I know how to get out". Lost all the friendliness and just turned and left.
I didn't see anyone suspicious outside, and neither had a neighbor I asked afterwards (and briefed) but that doesn't mean people weren't hiding somewhere. What I had figured it must be was her casing the house as you guys thought, and also I was thinking that if I walked her to the front gate (at least a 6 minute roundtrip) it would have been a perfect time for accomplices to do a quick run through via an unlocked door and grab whatever was visible. I figured her quick change in personality came after she saw me lock the deadbolt, which I would guess people (including me) normally don't do if they just step out front for a few minutes.
I'll never know for sure whether she was just a scammer kid, an innovative hooker, or part of a burglary outfit, but other posts here lead me to believe the latter.