Currently only service agent users can @ mention. We'd like to request this be available to all users.
I have so many requesters put @ someone and are confused why it doesn't link or why the person cannot see the ticket.
Oh! I was looking through requests and saw I voted on this one and they have since added this feature! You have to give Requesters the permission to Read: Users. We've had end users use this function on tickets which is helpful.