Maybe he needed the receipt to return the ladder for a refund.
LOL!
That is so typical at Home Depot. Meaning people buy all sorts of stuff. Then return it later.
People used to do this with snow blowers, lawn mowers, water pumps after a flood, air conditioners at the end of summer, etc.
Not as much anymore. Now, if you add oil to the engine. You own it. You have to deal with the manufacturer.
Years ago I bought an air compressor/nail gun kit there for $100 because it had been returned. It turned out the previous person had busted off the purge valve on the bottom of the tank. They had also stuck a two year old air compressor in a 2 month old box. Which is why they are supposed to match the SKU on the product with the one on the box.
Maybe he needed the receipt to return the ladder for a refund.
______________________________________
He must have known he was going up that ladder. Never coming down it. Never to be used by him again.