This seems to happen a lot. There are more than a few stories of people buying "refurbished" laptops, for example, at Fry's Computer stores in Silicon Valley with hard drives full of data from the previous customer.
It happened to me several years ago at Best Buy. I bought a supposedly new computer and tried to collect the rebate only to find out that it had already been collected by the previous owner, who collected the rebate and then returned the computer to the store, where Best Buy resold it as new.
I made quite a scene at the store, to convince them at last to give me a real new computer as a replacement for the used one they sold me as new. They finally agreed but I thought I might get arrested while there due to the hell I was raising.
I don't do business with Best Buy anymore.
YEP! I bought a SSHD from Fry’s and had all the personal photos from the previous 18-year-old Asian girl on there.
When I returned it and described the previous owners, their reaction was amazing:
They were aroused and did NOT conceal it. I was amazed.