#4 - June 28, 2010, 10:30 p.m.
There is indeed a way to tell if a whisper comes from a Blizzard Employee or not, Exolted. When you receive a whisper from a Game Master there will be a Blizz tag in front of their name. Their whisper will also show up in a special chat box.
It is also important to note that we do not warn that you
might be suspended. Either the account has been found in violation of our policies or it hasn't. If you had violated our Terms of Use and warranted a suspension you would have received a whisper letting you know that you were being suspended and to check your registered e-mail address.
If you receive such a whisper in the future, Exolted, please use the Report Spam option by right clicking on the persons name in the chat window and selecting Report Spam. That will forward a report for investigation.