If CVS is losing money selling vanilla reloads, then regardless of whether you are using them for a manufactured spend or not, they're losing money on a product they sell.
If I'm right that CVS gets the $4 fee, then they don't lose money on reloads that cost $80 or less. But you're right that they're losing money on all vanilla reloads over that price.
You are not making money off of CVS, you are making money from Amex rewards, and CVS is possibly losing money on selling vanilla reloads (a loss they'd have regardless of whether you're profiting or losing money through vanilla reload fees).
I don't know who to say that you're "making money off" because this isn't a precise expression. But what's true is that people who do this are getting money from CVS for free. And it is false that CVS would lose money on the purchases of individuals engaging in this strategy if those individuals stopped engaging in the strategy. So it's false that the loss CVS incurs as a result of this strategy is a "loss they'd have regardless of whether you're profiting". What's true is that they'd continue to lose money on the transactions of those people who buy vanilla reloads over $80 who were not engaging in this "manufactured spending" strategy. But I think that's a red herring. I am not criticizing people who buy those reloads without engaging in this strategy.
Companies take losses on products deliberately and often (they're called loss leaders). These are not oversights, they are planned losses with the company gambling that they'll make it up through the traffic through their stores. Or, is purchasing any of the other loss leaders at CVS unethical?
No, buying loss leaders is not unethical. I find it implausible that these cards are being offered as a loss leader. I think there's a moral difference between buying a loss leader and (say) scooping up 100s from a mis-loaded atm machine. Don't you agree that there's a difference here? Or would you be happy to take 100s from such a machine? In any case, I'd be interested if anyone has a reason to think that this is really a loss leader for CVS rather than a mistake akin to the atm example.
Is one really expected to try to figure out for each product one buys if the company loses money on it?
No. But if a company has made an obvious error (say, an expensive $1000 item somehow scans at the register for $1 by computer error), the ethical thing is to point it out. There's a relevant difference between this and being "expected to figure out for each product one buys if the company loses money on it". I'm suggesting: there is a morally relevant distinction between them engaging in a poor business strategy, on the one hand, and them *accidentally* messing up. Maybe it's hard to sustain this distinction, but I think I can see it pretty clearly.
Or what about all of the people buying products at CVS not at all on sale, is CVS unethical if they make too much of a profit?
No, that falls on the strategy side of things. Business is in some way a game of strategy, and, if everyone is playing the game, some will make bad moves. But its one thing to beat someone fair and square, and its another to take a 20 from them because they accidentally thought it was yours.
Or, are the customers the only ones with the ethical responsibility to make sure that the other party is really profiting from their choices?
Everyone has a responsibility to not take advantage of other people when they accidentally made an error. That's what I'm saying. If they are thinking (seemingly stupidly) that this is a profitable loss leader, then I'm ok with buying it. But I doubt that's what is happening. They didn't realize that they stepped in it with this. As soon as they do, the strategy will dry up. Meanwhile, its not very good to take advantage. So it seems to me.