i just tried this out on the web. if you reply to a tweet, and that tweet mentions someone else's name, your tweet will have both their names included just like

i just tried this out on the web. if you reply to a tweet, and that tweet mentions someone else's name, your tweet will have both their names included just like before (except their names are now in a link above the textbox). however if you want to remove their names, you have to click on the link, click on their checkbox to deselect them. so it's harder to remove people from a reply, and harder for others to remove you from threads you don't want to be a part of.