I sorta had this happen to me once. I have used "lsl" as an alias for long directory listings for longer than I can remember. And just out of habit it was almost always the first command I typed when logging into any box anywhere.

So one day I telnetted into a Solaris machine and immediately typed "lsl" before doing anything else. A short while later a colleague came to my cube. He had been snooping the hme1 interface and saw me login. He didn't need to trace the IP because he knew it was me when he saw 3 telnet packets with "l" "s" "l" in them.