IF A STUDENT DOESN'T do his homework, he gets a failing grade. Enough of those, he flunks out of school. In the process, he'll learn at least one thing: behavior has consequences.

That's a lesson that 16 principals in the Philadelphia School District need to learn, after they were found to be lacking certification for their jobs. And the consequences of behavior was what their colleague LeGreta Brown learned after the South Philadelphia High principal was outed for not having proper certification; she gave up her job. A district check after that incident uncovered 16 more; they've been given 30 days to fix it.

The district HR department messed up by not catching these lapses earlier, and we wish someone would suffer those consequences. But we can't help feeling that the responsibility rests primarily with the principals themselves. After all, they are supposed to be leaders - and they get paid well for it (according to the Web site of the Commonwealth Association of School Administrators, the union for principals, most salaries are well above $100,000, and come with 3 percent annual increases). At the very least, those principals should give back the salary increases for every year they've been out of compliance.

It's our money; we want it back. *

WE WANT OUR MONEY back from another debacle, too: the $3.9 million in public money to be paid to lawyer Jeffrey Rotwitt as a consultant hired by the courts to find a new location for Family Court. Rotwitt found a site, at the same time he was collecting development fees as a co-developer of the property in question.

The happy announcement of a long-awaited new Family Court building that Gov. Rendell, Mayor Nutter and Supreme Court Chief Justice Ronald Castille made Friday quickly turned sour when Rotwitt's double dealing was revealed by the Inquirer. He claims that the courts were aware of his dual role as consultant and developer.

Rendell, to his credit, acted swiftly and said that the original deal with the development group would no longer hold, and that the project would be competitively bid - which it should have been from the beginning.

That move will delay the project, which is OK by us. Castille owes the public an apology, and Rotwitt owes us the money he was paid.

Meanwhile, the state ethics board, the city ethics board and the Bar Association should join in taking a close look at how such deals can not only routinely happen, but apparently raise no eyebrows. *

BY ALL ACCOUNTS, the Board of Revision of Taxes has been a mismanaged, corrupt and inefficient assessor and collector of property taxes. And yet the board refuses to accept the reforms necessary to insure that taxes are fair for all.

For example, when Council drafted a referendum to dissolve the agency, the BRT fought it in state Supreme Court, unsuccessfully. In April, the board refused to renew a memo of understanding giving the city authority over part of the agency.

Last week seemed to finally end the saga, when voters overwhelmingly approved a ballot measure to dissolve the BRT. Then board member Russell Nigro said that he's considering filing another challenge in the courts, claiming that the city doesn't have legal standing to act.

On one hand, this should come as no surprise, since the BRT has shown little but contempt for the city's taxpayers for years. On the other, the arrogance that the board displays by dismissing voters' clear choice at the polls is outrageous. We're losing patience with the BRT's cockroach-like refusal to die. The agency should muster the last shred of grace it can, and just go away. *