Unencrypted password restricted pdf file asks for password

[jrvarma]

stapler asks for a password while processing an unencrypted pdf file which uses a password to restrict permissions. This is only an annoyance because I can simply press enter and stapler then processes the file flawlessly. In similar situations, pdftk does not ask for password, but prints the following warning before processing the file:

WARNING: The creator of the input PDF:
...
has set an owner password (which is not required to handle this PDF).
You did not supply this password. Please respect any copyright.

[hellerbarde]

Can you provide such a file? I can try to implement it without a test case, but it would make things a lot easier if I can test it myself :)

[jrvarma]

test-stamped.pdf