The reason is that they specify a boolean value as either "true/false" or "yes/no".
The last alternative causes problems not only for the Norwegian country code (no), but also in cases where you need to specify the actual word "yes"
You could of course end up with the same problem if you need to specify the literal "true" and "false", but by overengineering the acceptable boolean values, they increase the potential problem areas.
A Boolean represents a true/false value. Booleans are formatted as English words (“true”/“false”, “yes”/“no” or “on”/“off”) for readability and may be abbreviated as a single character “y”/“n” or “Y”/“N”.
Regexp: y|Y|yes|Yes|YES|n|N|no|No|NO|true|True|TRUE|false|False|FALSE|on|On|ON|off|Off|OFF
But if people have colons in filenames, for example for timestamps, all bets are off, and make chokes spectacularly.
/s, in case it's necessary.
Which seems like a pretty reasonable trade-off for something that's free.
$ cat Makefile
a\ file: ; echo 123 > '$@'
$ make
echo 123 > 'a file'
$ cat a\ file
123http://savannah.gnu.org/bugs/?712
That being said… In projects I just avoid filenames with spaces in general