Does Ed Sheeran have Cryptomnesia?
Cryptomnesia (or inadvertent plagiarism), occurs when a forgotten memory returns without it being recognized as such by the subject, who believes it is something new and original.
Blurred Lines: Did Sam Smith Cross Them?
Whether or not one ultimately gets busted for a transgression, premeditated or not, depends a lot on the zen of the infringee. And you can't get much more easy going than Tom Petty...