Au pair living with us, age 20. She babysits approx one night a week, has done so for about six months, kids (4yo twins) have never woken when she has babysat but she knows they do wake occasionally.
Recently she has a new boyfriend who she is spending every waking moment with other than when she has other commitments. We have said he is welcome in the house but not overnight between midnight and 7am - this was our agreement with her before she moved in.
Last night she was babysitting and our front door camera pinged on my phone so I checked the notification and saw that she had walked out of the house and closed the front door. I thought it was odd but thought maybe she had gone out to put something in the bin (right outside front door) so waited a minute or two and then checked to see if she had returned - she hadn't. I panned the security cameras around the front of the house to see if I could see her and could not. They cover the whole of the driveway so probably about 5 metres from the house plus neighbour on one side's driveway.
At this point I panicked that she had forgotten she was babysitting and called her. She said she had gone out to talk to someone and was right outside the house - demonstrably not true as cameras couldn't see her. Boyfriend also drives a distinctive van so I would have seen that on the camera too if it was across the street or next to the house.
I said I was not comfortable with that and could she go back to the house, and reminded her that she could have a guest inside if she wanted to. Three or four mins later she went back inside alone. As soon as we got home around 10.30pm she went out with boyfriend until 4am.
Ironically about an hour after I had asked her to go back inside while babysitting, DD did wake and she needed to settle her which she did successfully - they are very comfortable with her, she does the school run and after school care three days a week.
I have asked to speak to her straight after kids bedtime today as want to understand what was going on in her head to make her leave two four year olds alone out of earshot with no way of her knowing if one of them was crying/looking for an adult in the house. I am feeling really anxious about this and want to check if I am being unreasonable.
YABU - stop stalking her with your cameras, kids are fine.
YANBU - this is crazy behaviour and needs a serious conversation about responsibilities around children.
To add, until boyfriend appeared we were very happy with her. Since boyfriend she has been very distracted and trying to wriggle out of some of her responsibilities to us, but nothing that has made me feel the kids were unsafe until this point.