TLDR: What would be the chances of performing a successful Replace By Fee (double spend) before the block gets confirmed?
Scenario: I own a computer shop in Yangon, and I am looking into accepting Bitcoin payments at my shop. I am fairly new to crypto and I recently read about the Replace by fee (RBF) feature. My concern is: what if a customer comes and buys a MacBook or any product, completes the purchase with Bitcoin, then leaves the store and re-broadcasts a transaction with slightly higher fee back to themselves within the next 10 minutes.
How likely are RBF successful? Is there any way I can prevent this?
Thank you!
don't accept transactions as paid until they are confirmed on the blockchain---full stop. once a bitcoin transaction has one confirmation, it's extremely unlikely to be reversed.
some people will tell you to accept zero-confirmation transactions as long as they don't flag RBF, but they're wrong. a transaction is worthless until it's confirmed on the blockchain. it is very trivial to "double spend" an unconfirmed transaction whether or not it flags RBF.