Not a whole lot of "proof" without using the coupon. They're 100% legal. I can assure you I am not going to scam for $25.
Do they have an expiry date? Can it be used against all products? Is there a minimum spend? Is it limited to certain countries? Are there any other limitations?
Not trying to sound picky but I'd like a Hero 4 but I'd need to save the other 60%