It happened to me. A TV intended for someone else ended up at my front door, and I had to chase the delivery guy down. Not even the correct street. It was shipped from Walmart, no signature required.
The law does not declare misdelivered merchandise to be a "free gift" like unordered merchandise.
In fact, the code states: "Whoever, without authority, opens, or destroys any mail or package of newspapers not directed to him, shall be fined under this title or imprisoned not more than one year, or both." 18 USC 1703
hypothetically, what would happen if you kept the TV, leaving it unopened for a month or so (so you can be sure nobody wants it anymore), then used it yourself?
I don't know but people do it all the time when receiving large quantities of narcotics or merchandise paid for with stolen credit cards. You write "return to sender" on the parcel and leave it unopened by your front door. Sounds like a bad urban legend akin to "if you ask an undercover cop whether they're a cop, they have to tell you" but plenty of people still do it.