The problem is, if I'm understanding it reduced to its simplest level, relying on transaction information that is NOT YET ON THE BLOCKCHAIN. It kind of boggles my mind anyone could base any reliance for verifying deposits to a system on anything whatsoever not on the blockchain, even for tracking purposes.
Not only relying on information that is not yet in the blockchain, but also not paying attention to relevant information in the blockchain because you think you preliminary information is canonical.