It seems like I'm missing something in that you are able to mount the encrypted partition without a password.

What's stopping me (or the police) from stealing your hard drive, booting into my own Ubuntu installation, and mounting your encrypted partition?

Is the lesson learned here not use use Ubuntu disk/partition encryption?

Yes , brianck,I was able to mount the partition without a password once I reinstalled Ubuntu

So you mounted a hard drive and copied some folders from the command line. Big deal.

Besides, if you could mount the drive without using any password, it doesn't seem like it was encrypted at all.