YSK: Most customer service live-chat agents can see what you're typing as you're typing it. If you type something out and then erase it before hitting send, they probably still saw it.
from /r/YouShouldKnow
YSK：大多數客服即時聊天代理可以在你打字的時候看到你在打什麼。如果你打出一些東西，然後在點擊發送前擦掉，他們可能還是看到了。