At USU when they switched to the semester system back in 1998, they changed from 3 digits to 4 digits to distinguish between the quarter system and semester system courses. I've never done the math on it but always wondered how much it has actually costed over time to have all the extra zeros they added to the end of every course code. At the time, they still printed course catalogs. I don't know if they even do that anymore. Whether it's incremental ink or digital storage space, it's probably not much more than several tens of thousands of zeroes, which would be a few hundred printed pages or several megabytes spread over more than a decade. I'm sure that by far it cost more to make the switch than it has been to deal with the extra zeroes. The nice thing is that recently they started allowing departments to use the extra number as something other than zero, so you could have a lab just differ from the corresponding course by the last number, for example.
At WGU, the codes are quite different, but they have realized that their numbering system needs to change. They are currently 3 letters followed by 1 number. It used to be that the first two letters were something to do with the name of the course (like basic math started with QL for quantitative literacy). The third letter was a code stating what type of assessment the course used, whether project-based or objective, and the number was supposed to tell if the course was undergraduate or graduate.
Every time something major happened to a course, the code had to change, so you can see that they're going to run out of codes quite quickly. In the mean time, you get some funny things here and there with the nearly random course codes that are generated since the ones that made sense have been all used up. For example, a course I'm about to start teaching contains the initials of my boss who has been teaching that course. I might ask that they change the course to my initials if I didn't know they were already planning the renumbering anyway.
One course that's always been funny to me is AZC1. It's not like ROTF funny, just an interesting coincidence. The course name is U.S. Constitution, Law, and Citizenship. The way I always read it in my mind is Arizona Constitution, with the irony coming into play with some of the issues they are dealing with in terms of the citizenship or lack thereof of many of their residents. Without getting into the politics or what should actually be done to solve their problems, their situation has at least served as a useful mnemonic device as I try to remember hoards of less than meaningful course codes that seemingly everyone else has memorized. At least we'll all be on the same level when the codes change, and we all have to memorize them anew.