If someone wants to make a tutorial he can make a tutorial. There is no such thing as ''owning'' a trick, it's overrated. No-one can be sure that it has never ever been done before, it's impossible to be sure you have invented something/found something new.
Garner gets credits from me for showing this trick, and I don't say that I think he hasn't found something new! All I say is that ''owning'' a trick is overrated since you can never be sure...