Being able to tell when a player mutes you ingame

I noticed this when I annoyed my friend to the point that she muted me in-game. I didn't know that I was muted at all and this bug tipped me off, which might cause people to rage/troll in games if they found out they were muted.

My friend killed an enemy champion worth shutdown gold and I saw the +30 or however much it was on my character while walking back in to lane, but no chat message. The chat message wasn't there because she muted me.