I think this worry about abuse is totally disproportionate. Sukysue says she has seen more abuse than she cares to say. I was a social worker for over 30 years so I've seen a great deal of abuse/neglect and god knows what else. However I agree with Seeker that it's all the more reason not to let a skewed view of the world impact on your children.
It is true that when working with families with problems that the abnormal can begin to see normal, especially if you are doing it for years and years and I think that's why doctors and nurses sometimes appear indifferent to our aches and pains. That's another story so won't hi jack the thread.
Someone says they are worried about when the child goes to secondary school because you don't know the parents. In these situations you would surely phone the parent first and insist on taking your child rather than having her picked up and you can soon get the "lie of the land" - shouldn't be a problem.
Children can get abused anywhere - paedophiles are predators and will seek children out. They will be anywhere where there are children/young people. They will get jobs as assistants in chidren's homes, youth club workers, tennis coaches, cubs/scouts, nursery workers, teachers, transporting disabled children to clubs ete etc etc. I actually know someone who was involved in all of those things, and did a lot of damage before he was found out.
Just thinking that it would be very difficult for the bloke who lives in the house (father of the host child) to walk into a room with about 6 kids in beds and sleeping bags to clamber over them all and start to abuse one of them...........can't see it somehow.