Eh.. sitting in front of the computer for long hours?
I didn't even know that -r was a valid option. Gnu cp seems to treat -R and -r the same, but all 3 of the BSDs' man pages do not list -r as an option; instead they say this near the bottom:
Historic versions of the cp utility had a -r option. This implementation
supports that option, however, its use is strongly discouraged, as it
does not correctly copy special files, symbolic links or fifo's.
edit: and here's a simple example of how you can see that the shell expands filenames, not cp:
% echo *.c
blobmodule.c mlist.c mlist2.c mlist3.c mlist4.c mlist5.c
Now if I take out the echo, I can just type the glob, and the shell will then try to execute whatever the first word in the command is:
% *.c
bash: blobmodule.c: command not found