[vbrenny]

Well.. the whole ideia is to give out the message of 'I'm busy'. I have coworkers that use unplugged headphones, just to get the message delivered. Of course, it works only if other people understand this signal.

You can try to use some form of humor to disguise it.. try a little warning sign with something like 'DO NOT DISTURB: Genius doing science'. People will, at least, stop at the sign to take a closer look and you will be aware that they are coming, not scaring you.