There's something weird about the removed messages in chat. I saw this in the Electrical Engineering chat. @ThePhoton said something, removed his messages so that we could only see "(removed)", but for some reason his messages were still visible in the chatlog.
You can see the message here.
Additionally, we did some checks in the EE chat ([permalink]). Short version:
Some users could see @ThePhoton's messages as well, some users couldn't
@ThePhoton couldn't see his own messages in the transcript, not even a placeholder
Other users couldn't see anything in the transcript of the sandbox
@ThePhoton only meant to say old-fart-stuff
I can't figure out what's going on here, but I don't think it's by design that I can see removed messages.