This is what happened with Haiteng Wu, a 32-year old who was recently convicted of attempting to defraud Apple out of more than $1 million worth of counterfeit iPhones. According to the Justice Department, this was a scheme that occurred over a three and a half year period.
What happened is that Wu took counterfeit iPhones from Hong Kong with spoofed IMEI and serial numbers that corresponded to authentic iPhones. He and his conspirators then took those devices to Apple claiming that they were legitimate devices under warranty, and then received real iPhones as replacements.
Those real iPhones were then shipped back to Hong Kong where they were presumably sold for a profit. Wu and his conspirators were eventually caught and arrested back in 2019, and was recently convicted and sentenced to 26 months in a US jail, while also being ordered to pay $987,000 in restitution.