Hi,
I have been a babysitter for many years now and have sat for several parents who have wanted to stay out very late, eg- past 1.30-2.00am. I usually opted to stay the night because I could go to bed and rest/read/doze untill they returned. (I found it impossible to really sleep till they got back)
I fully expected to be paid until the parents returned, whatever hour that was, because YOUR RESPONSIBILITY AS A BABYSITTER DOES NOT END WHEN THE CHILDREN ARE ASLEEP!!!
As far as money, I charge an standard hourly rate untill midnight of £5.00ph. This goes UP after midnight. Time and a half! I don't feel this is unreasonable, as I am 28, have 15 years of b/s experience and am a fully qualified nursery nurse. I did charge less when I was younger, naturally, but then everything cost less then didn't it!(I used to get paid £1.00ph when I first started aged 13)
A friend of mine will do overnighters where the parents don't come back till the next day and she charges a set amount for the whole period with agreed arrival/departure times.
Definatetly think your aupair should be paid until the parents come back, if they are not happy with this, tell them to find another sitter. In my experience, the most likely time for young children to wake up is in the early hours of the morning, after having had a few hours of sleep. Expecting a babysitter to deal with a child who lets face it, only wants Mummy or Daddy at that time of night, without being paid is imo totally NOT ON
Sorry, I always go on and on, but childcare, in any form is something I care a lot about.