How about this for crazy. Adorama wants to charge $260 for shipping USPS to Hawaii. IF I ship to someone one the mainland with the free shipping, I wonder if that would confuse the rebate?
I am not aware the rebate cares where your mailing address is in the US, however, the loaded credit/debit/gift card received may not be applicable to purchases outside the USA. Read the fine print on the rebate or give them a call.
I do not recall if any of my rebates cards had my name on them, but I do know anyone can use them, so I doubt it matters where the card is mailed to initially, such as your friend in the Mainland.