I've build a DHCP-server today on a VM using Ubuntu 8.04 just to play around with. As part of the exercise is hardening the system I found some odd behaviour.
To protect me from my own mistakes I thought it would be nice to alias the commands rm, mv, and cp and each time ask for interaction. This is when I noticed that the commands mv -i and cp -i actually ignore the -i. I've tested it with --interactive but the same here. There is no problem for rm.
I've reported the bug at launchpad and it is now known as Bug 247973.