Claim: Adding “no copyright infringement intended” or “I do not claim ownership” to a YouTube video will make it legal.
“No Copyright Intended” has been added to so many YouTube videos, that Google explicitly addresses the phrase on its What Is Copyright page. Along with other unsuccessful approaches, like giving credit or purchasing the content, adding a disclaimer about your intent doesn’t affect whether your video violates copyright.
You can still violate copyright, even if you state that you didn’t intend to.
Imagine if it were possible to exclaim “no assault intended!” immediately before punching the ice cream man, and “no theft intended!” before clearing his stock. You wouldn’t have long to enjoy your treats before your arrest, despite your claims about your intent.
The core of copyright law is that creators have the sole ability to determine when, where, and how their works are displayed. The relevant question isn’t your subjective intent, but whether the creator was deprived of their ability to control their work. If you intentionally uploaded a video, and the video violates the creator’s copyright, then just as with punching the ice cream man, your intent to violate copyright will be presumed.
Fair use protections may apply, but this is independent of any disclaimer. There are unfortunately no special words or disclaimers that make an infringing video non-infringing.