You should be EXTREMELY CAREFUL when using this strategy. It is, at a minimum, against airline policy.
If you have any kind of airline status or membership, and you do this too often, they will cancel it. If you try to do this on a round-trip ticket, they will cancel your return. If the airlines have any means of making your life difficult available to them, they WILL use it.
Obviously you also cannot check bags when using this strategy, since they will go to the wrong place (your ostensible, rather than your actual, destination.) This also means that if you have an overhead-sized carryon, and you board late and are forced to check it, your bag will NOT make it to your intended destination; it will go to the final destination marked on your ticket. If you try to argue about this, you run the risk of getting your ticket cancelled altogether, since you're violating airline policies by using a ticket in this way.
I bought a visa prepaid debit card that's expiring in a month. I have a bank account. How do I get the money from the debit card (anonymous, not attached to my name and has no online account associated with it) into my bank account? There's no payment gate in my online bank account.
I was able to use Square to transfer money from a pre-paid gift card (not sure if it was Visa though) to my bank account. Transaction fee is ~2.75% iirc.