There are a lot of flakes out there and there is more to filing a DMCA that I would have thought.
IANAL and anything I state is just opinion, shouldn't be taken as legal advice nor should anything anyone else posts on a blog or forum be taken as such. If you're really concerned, hire a lawyer to do such things or use your legal mailing address, which in many cases I've noticed people use a PO BOX (assuming you have one and it's legal to use for such matters).
Gee, using a PO BOX must be legal, <smirk> as someone I once unfortunately did business with once had their business address registered with the city as a PO BOx. For some odd taxevading reason the city was real pleased when I gave them the actual address of this so-called business. ;)
Lots of craziness out there, you really can't avoid it, just be careful.