The game correctly filters out a blocked person's chat and their emotes from all chat channels.
However, any sounds produced by players on your block list still play, so if they decide to harass you by spamming performance notes or emotes that produce audio, there is nothing you can do about it.

Additionally, if Timmy is on Bob's friend list prior to Timmy blocking Bob. Then Bob can still see that Timmy is online, and where Timmy is, so harassment is still an option.

I'd like to see this addressed. Thanks