Definitely this is a personal decision. I chose to tell a few people and it has worked out ok but it's really what your comfort level is.
Just keep in mind that you may get questions if you are not eating or hobbling around. Not saying you have to tell them why, just be prepared how you want to field those types of questions if they come.
Congrats on your upcoming surgery!!!
Source:
http://www.lapbandtalk.com/topic/161729-to-tell-or-not/