Peter,
I disagree with your position. If I add you to my Junk email senders list you do not get a notification and all messages from you get rerouted into my junk mail folder which I may or may not read.
The twit filter is the same thing. If I get tired of reading garbage from someone who seems to be often posting garbage I should be able to twit filter them without making any comment as to why I choose to do this and without the need for me to reply to any inqueries from that person. If I miss information because I twitted someone that is my problem and not one else's.
I think the twit filter the way it is works fine. It has worked fine for a number of years now. Those who choose to use the filter seem satisfied. I don't choose to use the twit filter at all. The only people complaining are those who have been twitted.