Comment 1 for bug 814908

Checking for presence of the file /var/run/cups/cupsd.pid to find out if cups is running is more robust in my opinion.

Anyway if you think lpstat -r needs to return nonzero value if cups isn't running this should be reported upstream to CUPS here:
http://www.cups.org/str.php
Please also add a link to the upstream str in this bug report.