Does your email program have a confirmation step after its "Send" button?
Confirmation steps, in practice, don't really help. After a few uses, people build up the muscle memory that "action, confirmation" is the action. Then the one time in a hundred they want to cancel, they don't realize until too late.
One approach to try would be, for any purchase over $5, make a "confirmation step" that looks like a restaurant bill, and require the user to sign it (with their finger). Perhaps "sign name next to a big number" would be enough to jar them.
But really, the solution is to make it undoable/refundable. No matter what barriers you put up, somebody will do it by mistake (guaranteed), and is going to want their money back. If I can return a $1000 jacket in real life, I should be able to return a $1000 no-op app.
Confirmation steps, in practice, don't really help. After a few uses, people build up the muscle memory that "action, confirmation" is the action. Then the one time in a hundred they want to cancel, they don't realize until too late.
One approach to try would be, for any purchase over $5, make a "confirmation step" that looks like a restaurant bill, and require the user to sign it (with their finger). Perhaps "sign name next to a big number" would be enough to jar them.
But really, the solution is to make it undoable/refundable. No matter what barriers you put up, somebody will do it by mistake (guaranteed), and is going to want their money back. If I can return a $1000 jacket in real life, I should be able to return a $1000 no-op app.