I demand that any voucher program requires all schools accepting the vouchers must:
accept all student regardless of academic ability and/or special needs
require all schools be required to participate is standardized testing
require all school to have the same auditing conducted with public disclose of the results
require all schools to allow public use of facilities during no school hours
pay a share of school busing cost  based on student users

The above list has been bantered about many times in the voucher battles.  The private school sector has been opposed to putting those restrictions in-place while the take the public funds.