This actually how Quest does it. Imagine my surprise when I was setting up the router and had to call and ask what the router password was and the tech said, "Yeah, just flip it over, under the serial number is a long hexadecimal code, that's your password."

At least the password was somewhat strong. I'm not sure having it printed on the same label as the serial number is a good idea though.

I don't understand the problem with having it on the same label as the serial number. Can you elaborate?

To me it implies that the default password can be determined if you are able to discover the MAC address. Either the manufacturer might have it in a database that could be compromised, or the algorithms generating the MAC addresses and the pseudorandom default passwords might be reverse engineered.

This is often the case with WPS on home routers. Here's a blog post detailing the reversing of D-Links WPS PIN generation.

http://www.devttys0.com/2014/10/reversing-d-links-wps-pin-al...