I guess it is pretty much perjury penalty risk free to make such DMCA declaration from outside of US:

>Declaration: I have taken fair use into consideration. I have a good faith belief that the use of the copyrighted materials as described above is not authorized by the copyright owner, its agent, or the law. I swear, under penalty of perjury, that the information in the notification is accurate and that I am the copyright owner or am authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.

Unfortunately, that penalty has no teeth, regardless of where the filer is.