Buy a Volt, return it, get a $7.5K tax credit

Tax Consequences of GM's 'Love It Or Return It' Promotion.

Plus this:  Tax Implications: You may be subject to federal, state, or local tax on any benefit paid. You should contact a tax advisor/consultant if You have any questions regarding the tax implications associated with this program.

So, if the car you return with 3.9K miles on it is worth $5K less than a new one, are you responsible for tax on the $5K "benefit"?