The short answer is no, SI security doesn't override Sage 100 ODBC security. More below:
Intelligence uses ODBC to access Sage 100 data. Therefore, use the ODBC security tab in Sage 100 (not SI) Role Maintenance to limit access people to the data used for Intelligence reports. If a user runs a report which relies on data for which access has not been granted to the user, the report will come up blanks for that data.
Still, you are able to use SI security in order to limit the Report Viewer list but it's a limited solution at best in my never-to-be-humble opinion. Basically, I would just use it to keep the list of manageable size.
Further on the subject of security, Sage Intelligence keeps all of your report templates in the Report Repository. It's imperative that the location of the Report Repository have server rights set up to limit the access people have. For example, if you put the Report Repository in your main MAS90 folder, or your HOME folder, it may inherit those rights. If so, you may have inadvertently ""leaked"" information to looky-loo employees.
As a test, I used Windows Explorer to double click and open a template I wrote for a client a couple of months ago. Financial data was still visible on the spreadsheet template.