Right. And as an explanation of why you need to /who or /whois for IAL to work...
IAL doesn't just automatically fill up for you when you are on a channel. It will fill for each nick when the nick does something. For example, if you're on the channel and someone joins, changed their nick, types something, etc, then it will fill with their information. If you join a channel and try using a command on someone who was already in the channel and hasn't done anything besides idle since you joined, IAL won't be filled for that person. The way around that is to /who the channel or /whois the person to get the information to fill IAL.