Most businesses are only keeping copies of receipts for up to 18 months, and any transaction records for 3 years to comply to a potential IRS audit. A short enough time that it wouldn't prevent many people from getting away with faking the receipts. Further it would likely not be deemed worthwhile to pursue it this far because it will require a research fee and significant time for each business to produce this information.
My point is that dealers/manufacturers ARE approving expensive warranty repairs without receipts, and your own example showed that. You can speculate on why that is, but the reality is that the log of receipts is pointless and most dealers/manufactures know this. They simply inspect the condition of the vehicle and the oil at the time of the repair, and will proceed unless that leads to finding a root cause of egrigious negligence or misuse.
How Long Should a Business Keep Credit Card Receipts?. Customers have as long as 18 months to dispute charges on their credit card bill. If you do not keep the credit card receipts from sales transactions, your business could be forced to return the money
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