This question often comes up in projects once people start using the Excel Add-In with Dynamics AX 2012 and working through security. There are two functions from the Add-In to access data. One is Add Tables which gives the users the ability to inquire on any table in AX2012 and update the data. This requires that the user has system administrator permissions. There is a second function with is Add Data and this works on accessing the data either through the queries or a service. These can be secured through the security system. Here is a quick walk through of how the functions behave differently for two different users.