Yes - but there is another issue being missed.
First, youtube is not the place for magic. Keep it in house.
Write up your trick in ebook or put a video of it and the explanation on your website.
Then got to every magic forum and post: free trick. It has come to my attention that an effect I created in (insert year) is about to be released by a magic company and will be credited to another magician. I had submitted my trick to that company and had been promised they would release it. Given their current decision, I have decided it is in my best interest to share my idea with the community and insure, at least, proper credit is ascribed. Feel free to visit my site and I hope you enjoy the trick.'
Hit genii forum, magic cafe, magic bunny, magic talk, magic woods (those are the big ones that come to mind).
Now - here is where Cedric and I differ - do NOT name or accuse the company!
One, you open yourself up for liability. But more importantly, as they have yet to release anything, you are engaging in speculation AND give them the opportunity to change or not release the product making you out a liar.
Just get your product out there and in everybodies hands before they do.
They cannot fault you for that, it's your idea.
And if they do try to fault you for it, or accuse you of anything, it becomes tantamount to an admission of guilt on their part. (Or at least establishes that there was contact between you and them).