It's no more dishonest then those people that go like, "Hit Me Baby One More Time - Britney Spears - [Remix] [Cover]" With the cover portion as the last piece of text that you can't see in normal search, haha.
The problem with using other people's tags is that google has all these algorithms and rating systems happening behind the scenes so you would need to make sure that their tags are relevant to your information. Because if you put in like "sxephil,ijustine,etc" and people click on your videos from being suggested and don't like and thumbs down and click away quickly then google learns quickly that your video isn't related or relevant and will stop bringing your video up to those tags.