USER MODE y

Usage: UMODE +|-y
Usage: MODE <nick> +|-y
y - Whois notices
This will show you who performs a WHOIS on you. Since most users do not realize anyone can see when they are being whoised, they may be surprised if you mention it to them. Also you should not take offense at being whoised unless someone is repeatedly whoising you as an attempt to flood you. There are numerous reasons to whois someone, such as to check their idle time.
But people who are whoising opers often desire help, and you can offer it to them or wait for them to message you.
Privilege: operator
Examples:
/mode jimmers +y
/umode +y