I have to say that given my previous employer's attitude towards having time off for sick etc children, I did start to lie that I was ill.
They were completely unsympathetic and actually dragged me into a disciplinary hearing as I had had 'too much time off'. It was 6 days in a month, bearing in mind that at the time I worked FT.
During that month, my younger daughter (3) had chicken pox, so 3 days off for that (my exDH helped too), we had a fire in our house so I needed a day off to sort a few things out, one of the days they talked about was a bank holiday, and finally, my exDH forgot to collect our 4 year old from school in the first week she was there at lunchtime, couldn't get hold of him, so had to leave immediately to collect her.
Having said that, my current employer is great, they allow me to work PT during school hours, and I wouldn't dream of lying to them, because I know that they wont hold it against me, rather they just wont pay me (which is fine)