Is there some way of putting a password on your email so that when someone else uses your iPad 2 they can not see your email.
I think you can go into settings -> general -> restrictions. Enable and check to see if your email is covered under restrictions. Not too sure as I dont have them enabled myself, but it's worth a shot. Good luck!
I think the main reason they have not included the password for email is that the iPad is a "One User Only Device" Apple has said a number of times that they do not plan on allowing multiple user accounts on their devices and I think this falls into that catagory.... I wish they would though..... maybe someday