RTB: Is the IUSD a typo and you mean TUSD? If not, I hate to break it to you, but it wasn't long ago (last year) when the district even considered booting the out-of-district transfer children of employees (which they have since decided to make an exception for). Now that IUSD is on the Basic Aid funding model, they are really cracking down to make sure the revenue is being used appropriately. If you really want to beat your brains out, you or your child's other parent could become a county education or IUSD staffer with a spot on campus and get them an approved enrollment that way. So, technically, where there's a will, there is a way. Otherwise, no. They were allowing transfers under the Revenue Limit model and now I hear there is talk of going to "Flat Funding", or at least that is what's proposed by Gov. Jerry Brown. If they switch models, it could open up the doors again. But, you know how that goes.
Fwiw, I'm an IUSD parent & classroom volunteer. It's over-hyped. Stay put.