I doubt that any of the high-profile melodic plagiarism cases has ever arisen from some moustache-twirling evil musician deliberately ripping off a melody. That's suicidal, and not guaranteed to produce a hit anyway. They all start with someone plagiarizing subconsciously.
If in fact the (unintential) plagiarism was real and the video record reinforced that, there would be incentive to withold the video evidence. But manufacturing evidence is extremely dangerous. It's like trying to spoof a journal from years ago — all it takes is one slip-up and you're doomed.
I don't know about high-profile melodic plagiarism specifically, but a lot of general plagiarism is absolutely intentional. So I wouldn't rule out the possibility for any particular sort of plagarism.
Sure, but a lot of general plagiarism is done because of laziness or the high reward/low risk math of whatever context it's in. If I plagiarize some code as part of my job and don't say where I got it from, it's unlikely anyone will care, or even see it, let alone know where I got it from.
Almost everything a major pop artist would put out has at least a shot at becoming a worldwide hit where a vast chunk of the population will hear it. To decide that you're going to plagiarize in that case, when you easily have a massive pool of songwriters and producers who could help you come up with something more original, AND to plagiarize a past #1 hit? You'd have to be pretty dumb.
I'd almost believe it was intentional more easily if they were plagiarizing some band I'd never heard of, or from another genre/country. The Coldplay/Satriani suit was a little more believable to me in that way, since it would be easier to go "eh, who even listened to that other song. No one will notice."
It's possible in the abstract but that doesn't mean it's likely. In particular, it seems ludicrous that Ed Sheeran has adopted the stratagem of deliberately ripping people off and then creating false evidence to hide it.
I doubt that any of the high-profile melodic plagiarism cases has ever arisen from some moustache-twirling evil musician deliberately ripping off a melody. That's suicidal, and not guaranteed to produce a hit anyway. They all start with someone plagiarizing subconsciously.
If in fact the (unintential) plagiarism was real and the video record reinforced that, there would be incentive to withold the video evidence. But manufacturing evidence is extremely dangerous. It's like trying to spoof a journal from years ago — all it takes is one slip-up and you're doomed.