Ok, reverse this - it happened at MY house. My neighbour (who was a close friend) went on holiday and her friend (a single mum) was dog sitting for her. I had met this woman a few times, got on great with her, and our sons knew one another so they had been playing a lot in the garden as it was the school holidays. I felt a bit sorry for her as she didn't drive and we were stuck out in the countryside, she seemed bored stiff and keen to chat, so I invited her in for a coffee one afternoon, and she stayed so long I ended up giving her son dinner.
After she has outstayed her welcome a bit too long, I needed to go out to collect my other child from somewhere about ten miles away, so I told her I needed to go out, hoping she'd leave. She just shrugged and said 'No problem, the boys are happy playing - I'll look after them both and wait for you to get back. We can crack open some wine.
So, not wanting to appear rude, and being a very non-confrontational person, I left her there in my house, and drove off, feeling a bit uneasy and annoyed.
I was gone a fair while and my DH came home from work. He went into the bedroom to take his suit off, had no idea she was in the house, and she just appeared, as if by stealth, in the bedroom and started chatting to him while he was half dressed. 
She'd been upstairs for some reason. 
He made polite, stilted conversation with her until I got home, she was a cool as a cucumber apparently, not a trace of embarrassment or awkwardness, and then he pulled me aside and said 'WTF?' 
Mad stalker woman in my room!!!
She didn't leave as I cooked our supper, so we dutifully poured her some wine, and she stayed...gave her some supper (it was difficult not to) and she stayed....by the time she went home we were both in agreement that we thought she was a crazy woman. By the end of the fortnight we KNEW she was.