A staff of Roblox Today has a name that is either Blue, or Black. If a person who does not have either of those colors in their name, claims to be a admin, or moderator, report them. Faking a RT staff is strictly prohibited. We take precautions of stopping this, but cannot stop everything. But no staff will have a grey name. Remember, you can get banned for imersonating a staff member, so, DON'T DO IT!.

You can also view a list of staff here, note that it is not always up to date, name colors are the best way to check:

http://www.robloxtoday.net/t3377-list-of-staff