It is neither ethical nor legal.
The link below will take you to a thread on another site & you can follow along on the play by play.
The short version is that a guy bought a tag & title via Ebay & used them on his car. When the car came up for sale, it was confiscated & the title voided & the 'donor' VIN removed.
Ebay does have rules against selling them as well, but every once in a while the sales go through.
Link -
Here is one to avoid - JS23N0B141390 update! | Best of Moparts / Tech Archive | Moparts Forums