Is there any way to have a client based infopath form in a SharePoint forms library that prevents the users from saving the form and opening it in Notepad to see the values?
nope, i dont think it is possible..
That's kind of what I figured... I'll either have to hope that users won't know to do this or set item level permissions in SharePoint.
even if you set item level permissions infopath the items which a particular user has access to, he can download it on his machine and change what ever he want. however you can use managed code to sort of prevent this to happen