FIRST the state courts DO have the right to make the custodial parent waive the right to the dependent to the non custodial parent, this is in accordance with the IRS regulations. If the custodial parent doesn't like this situation then they need to talk to their attorney to get this changed however this situation is usually the result of a long fight to get to some sort of agreement that both parties can agree on. Failure to comply with a legal court order can cost you not only money but jail time.
Next, if the non custodial parent claims the child when they should not have done so they get caught when the custodial parent ALSO claims the same child for the same tax items which will require the IRS to send a letter to both parties instructing the incorrect person to amend their return. If neither person agrees they are wrong and amends their return then they are both audited and the loser gets to pay back the refund and/or credits plus penalties plus interest. In the case of the earned income credit they can lose the ability to claim that credit for up to 10 years. This is not fun for either party so it is best to agree to play by the rules.
