I think this is a really personal choice. Up until a few years ago i would have used babysitters and nannies and i am sure the majority of them are lovely, trustworthy people. Sadly a couple of years ago a friend of a close relative of mine hired a nanny for her 2 young boys through an agency and she became aware after a couple of months when she came accross a journal of the girls that she had been inviting her boyfriend around when the mum was at work and that they had been abusing the boys she went through a long process to prosecute but the point is you don't really know who you can trust. IMO you can only really trust yourself so i wouldn't risk it. But as i said before it would be in the minority that this would happen but it's very scary.