I have a boo boo log that I record any incidents. Any time something breaks the skin, I call the parents but bumps and bruises are part of being a kid and will let the parents know at pick up if something happened when they fell and a bruise might happen.
I have parents who have called asking me if something happened as they see something. I don't take it personally- either their little one had a clumsy day or I don't know how it got there.
You can't record every bump and bruise they get but I do my best. Once I have filled it out, I will email to the parents for them to have.
Nothing in my contract but boo boo log is in my package that I give to parents when they come for an interview.