No. The main requirement for a DMCA request to be valid is that it come from a real entity. If you sent them with a fake return address they wouldn't be valid D

No. The main requirement for a DMCA request to be valid is that it come from a real entity. If you sent them with a fake return address they wouldn't be valid DMCA requests anymore. That said, yes the DMCA can be abused. The check against that is the same check that exists against other kinds of fraud: it's illegal.