Are Christian schools Christian?

Via Neil A, Michael Jensen opened an discussion about Christian schools in Australia, where he asked "If Christian schools were really Christian, would anyone (other than Christians) want to send their kids there?" Good to think through before we send our kids to school in a few years. However, personal experience wise (yup, I've only done high school like 10+ years ago), I went to an Anglican high school (a sort of high'ish one). That did not help me to become a Christian, nor do I feel much "Christian" about it. Being a single-sex all boy school, sport was certainly the most-worshipped god there.