checkout works different with and without -r HEAD

[Aggarwal, Vineet]

When I checkout a project, not all files are checked out. These files
were created on a branch and the branch later merged to the trunk.
However, it works if I specify '-r HEAD' with checkout command. Similar
behavior is noticed with other commands such as rtag.
Is this how it should be or I am doing something wrong here? Also, what
is the difference between dead state and a file in Attic directory.

Regards,
Vinnie