Whenever I used the old Coventry mod, people soon noticed that x has disappeared altogether and will then say so in a thread.
If the mod could hide just "new" content from a user, so Tachy thinks he's being ignored and others think he's stopped posting; it would be better; but near impossible to implement. I've learned to live without such functionality, rather than mess about with ignores I just ban, getting rid of idiots is always better in the long run.
I also found that the troll cottoned on pretty quickly and I just got bombarded with dupe account attempts instead. So for me not a really useful feature. Same as the "Annoy User" plugin which xenfor has in the core as discouraging.
Although with discouraging you can at least do it via IP, however most persistent trolls aren't going to stick to a static IP anyway.