This is ridiculous. Rent a 300 dollar video card for 300 dollars, make profit?
Why wouldn't you just mine yourself, and KEEP the profit?
I don't understand how this sort of altruism COULDNT be a scam.
Additionally, your prospective client could use the 300 bucks to buy another videocard and slap it into his rig.
What you're literally asking for is "give me 300 dollars and I'll print you 450 dollars. Wow!"
if that was reasonable, at all, you would just print the cash yourself, and keep it.
This doesn't make sense.
I don't think is is a scam, at least not in an outright theft kind of way.
He wants to become a shovel vendor during the coming mining craze. He wants to lock in his profits and let the renters take the risk of the price volatility.
There's no way the deal makes sense to anyone with the ability to make and manage their own boxes, though.