Richard Bridge wrote, "I don't think that 's right, even in the USA. An unathorised use would still be an infringment." Richard is technically correct.

However, unless and until you have registered your copyright with the US Copyright Office, it would be very difficult to impossible to collect any retroactive licensing fees, let alone damages. That's because the burden of proof would be on you to show that (1) you are the rightful copyright owner, and (2) the other party actually knew you were the copyright owner and either willfully or negligently infringed on your copyright. Registering your copyright takes care of both issues and shifts the burden of proof to the other party.

Registering your copyright is such a simple thing to do, and it costs as little as $35 and no more than $45 for an entire collection of songs. It provides prima facie proof that you are the rightful copyright owner, and it gives legally sufficient notice to the whole world. Furthermore, it's the standard practice in both the legal world and the music industry. I cannot see any good reason to do otherwise.