cupsenable "may ask the user for an access password"

[Kenneth Moyle]

I accidentally ran cupsenable as me instead of root and got:

moylek(103)cupsenable lp3
Password for moylek on localhost?

Entering my password just resulted in repeated prompts.

According to the cupsenable man page:

The CUPS versions of disable and enable may ask the user for an access password depending on the printing system configuration. This differs from the System V versions which require the root user to execute these commands.

http://cups.org/documentation.php/man-cupsenable.html

"May" require?  Depending on _what_?  I can't find the docs for this feature.  Anyone know what I have to tweak, poke or felate to enable use of cupsenable by users?