I've had a similar idea for a while now.
I would like to expand on the plan a little though.
1: make a small piece of SW, that generates random garbage files (of user specified sizes)
2: Distribute this SW to anyone interested.
3: Routinely fill unused areas of your Harddrive with files generated using this SW.
4: Hide any (encrypted) files you have among these (you could have a whole series of files named myfile1, myfile2, etc. and then let the actual file be number 11 in all cases so you can find it again easily).
5: Transmit these nonsense files to other users who you also send encrypted files to (or to people you don't send encrypted files to - you can always add a note saying that the file is garbage - even if it is actually not).
This would enable you to always claim that any encrypted file found on your harddisk is just a garbage file "See - I have a program that generate such files".
It would also mean that anybody trying to break encryption on your mail would have the added problem of determining whether the message was indeed a message or simply garbage.
Potentially this could bring Internet snooping operations to a halt if enough people started doing it. Breaking the encryption on total garbage takes infinity time and ressources :-)
I don't know whether this would make the world a better place though. There is probably a way around this method too.