It doesn't seem to have occured to apple that more than one person might be using the iPad. Let's face it, in their mind we should each have our own individual iPad and virtually share stuff with each other. But that is never going to happen as they are way to expensive.
Back in the real world we are not all that rich, so the iPad is forced to be sharded within my house at least.
So now that I have set up my email on the machine, everyone who uses it can read it, and send emails from my account! There is no way to lock it or password protect. I can lock the entire machine, but not the email!
It would be great if you could set up different users for the machine, so that everyone has there own login. That way each user could arrange there apps how they see fit and only have access to there own data. Oops, sorry, that would make it useful.
What it comes down to is that Apple say that the machine is great for sharing becuase there is no way of locking any of your data. So for Sharing read insecure.