The first time we used sitters, it turned out to be someone I vaguely knew. She was a local childminder, and I was 99% sure DC's wouldn't wake up, so I wasn't too worried. She bacame our regular sitter
There was a time however, when one of DS's nursery teachers was going to baby sit for us, but became very ill at the last minute. It was a big do we were going to. DH was giving a speach, I was on the top table, new dress, manicure, profesional blow dry (you get th picture) Anyway, Sitters found someone at 4pm who could come at 6 pm. I did feel a little daunted that I had no idea who she was, but she turned out to be an absolute star. She spent ages reading to my boys, and playing games with the older one. DS2 even asked why the baby sitter only pulled the duvet up and said goodnight, instead of lying in bed with him, like we do.
Remember,all Sitters are CRB checked, and most are nannies or childminders. Enjoy your evening.