The Sacramento City Unified School District learned the hard way the meaning of the old saying, "Anything that looks too good to be true probably is." Other public entities thinking they can avoid the law that requires public employees to participate in the California Public Employees' Retirement System (CalPERS) and Social Security should take note.

The school district is going to pay dearly for allowing administrators to cook up a scheme under which they'd opt out of CalPERS and Social Security in favor of a newly created plan, the California Administrative Services Authority (CASA).

What makes the idea a sham is that district administrators had to make it look as if they no longer were district employees. They took a "leave of absence" from the district and became "employees" of CASA, then immediately returned to the school district as "contracted" employees - same job title, same work, same pay. The school board let them do it. It turns out that was a serious mistake.

The danger always was that CalPERS and the Social Security Administration would conclude that CASA employees were de facto employees of the district - which they obviously were - and, thus, required to participate in CalPERS and Social Security.

Well, CalPERS has made that determination. It's only a matter of time before the Social Security Administration does, too.

There's no reason to wait for that. At its April 1 meeting, the school board should end the district's participation in the CASA scheme and have administrators rejoin CalPERS and Social Security. Then the board should negotiate a settlement with CalPERS and the Social Security Administration to avoid ruinous lump-sum liabilities for back contributions of $3.2 million to CalPERS and a similar sum to Social Security.

School board members went for the CASA scheme because they thought it would be "cost neutral" to the school district. That was an illusion from the start, but even if it had not been other issues should have attracted the district's attention. Both CalPERS and Social Security depend on full participation to achieve their public purposes and financial solvency. Dubious schemes that narrow the contribution base have an impact on everyone else who pays into those retirement systems.

And speaking of paying: The school board failed the public financially and ethically in falling for the CASA scheme. Now we're all going to pay.