Hi @MinuHa,

I do think the answer right now is a "no".  There are some other areas fo Canvas, like the Assign-to boxes where this has been remedied by adding some additional information (the sis_id) below each person's name.  For discussion @ mentions though, that probably isn't as workable of a solution because students can @ mention too and they probably shouldn't see other users info or wouldn't have the meaning behind it like a teacher would. It could perhaps help a teacher, but I think Instructure would probably look for a universal solution.  This is definitely a tough one, but I hope this info helps in some way...

-Chris