It is not fraud, however you wouldn't be able to return the defective phone at Best Buy since they match up the ESN, which wouldn't match the phone you were returning. You would end up just paying $400 as per AldousSnow's post. All the phones are tracked to the ESN from which they were purchased, so all you would really be doing is reseting your eligibility for no reason, and just end up paying full price for a second phone. My advice would be to wait and just deal with it, they are going to be bitchy about returning/exchanging phones so long as there is still a shortage. When they finally have a surplus, you can probably just complain to a Sprint store manager and get an exchange, or take it up directly with HTC.