That's what I get when I try to send a /tell to someone I have blacklisted.

Will that person see any warning on screen (or in chat), similar to the one I get when sending a tell to someone on my Blacklist, to notice them I am on their blacklist?

I heard they only get a message if they try to send you a party invite.

Also, bonus question:

Do people get any message when I'm in /busy status, in the same way you get a "target is in duty and couldn't receive your tell"?