My 2 cents on the post by Rusty above:
At the end of the day, i think the school's rationale here is for them to think of the school as a business and not a catholic school. Let's face it, would the school impose such policies if parents settled their childrens tuition fees etc. with the school in a timely manner?
It's a business that needs to stay afloat regardless of its religious orientation.
Sure, it's not a Christian thing to do. But again, would they have resorted to such strategies if obligations were settled on time?
My wife and I work hard to put our kids to school. But i certainly would not blame the school if they imposed such policies on us should we fail to fulfill our obligations to them.
IMHO, it's a better option than saying "Well, you cant pay your dues to the school your child goes to? Get him/her the *%!@ out of here then"
Mejo double edged sword ito.
As a Christian, it definitely is not the thing to do.
As a business however, it's an option one should consider.