Here's why it doesn't work: i have mailed myself an unsealed envelope every day for the past year and will keep doing it every day from now on....the day your movie makes $100 million, i will search google, print the script out, then put it in one of my unsealed envelopes from a couple years ago. I'll seal the envelope and run to court with proof that you stole my idea!! hahah!
it's called a poor man's copyright because the postal date seal is govt issued and therefore supposedly valid. If you had mailed your own script to yourself and did not open it, the reasoning is that the date it was stamped is proof that it existed and was in your possession at said time.
But copyrighting and registering with the WGA is not that expensive, and if you value your work and think someone might actually want to steal it because they actually could profit from it, then the amount you pay is worth it.
I think I paid around $100 for the script I'm producing now. I liked it enough and was about to send it all over the internet to special effects guys, pyro technicians, and other film people, so I wanted the protection.
hope this helps!
