I used to have a job working on the help desk of online PC manufacturer in the early 2000s. We had a customer who claims their PC had made a loud bang and smoke had come out of the back of the PC, 1 week before their warranty was due to expire.
When it was received back it was found that the scorch marks were actually caused by the customer using a lit candle to make it look like something had blown and they had inadvertently dripped molten wax all over the inside of the PC in their attempt to make it look like it had developed a fault. Yet when confronted with this they swore blind not only that they had not done it, but that they don't even own any candles.
As it was despite their efforts the PC booted up without any problems and so was shipped back to them, minus the candle wax.