I don't know how employers get away with that Kathryn. To cover themselves they should just say at hr's discretion. I whinge about my old work, but I took quite a lot of time off when my two were sick. And got full pay. I did feel guilty, but when one child has swine flu, and the other in hospital with flesh eating disease I would have flipped my lid if they said anything.
Also had to go back to NZ when my mum was ill when my son was 10 months. She died a few weeks after, but then my son was ill there so couldn't fly. Then when all was fine I decided I wasn't going to travel all the way back here with an 11 month old as I was due back in NZ 4 weeks later to get married. I fully expected them to threaten to fire me, or at least not pay me. I was off for a total of 3 months, and got full pay for the lot. Very shocking.