Is there a way to ensure the BitLocker To Go Reader is not installed on FAT-formatted drives?
Yes. Group Policy can prevent the application from being installed on the drives. The first option is to disable the policy settings that allow computers running Windows Vista, Windows XP with Service Pack 3 (SP3), or Windows XP with Service Pack 2 (SP2) to open BitLocker-protected data drives. These policy settings are located in the Local Group Policy Editor in Windows 7 or the Group Policy Management Console in Windows Server 2008 R2 in the following locations: Computer Configuration\Administrative Templates\Windows Components\BitLocker Drive Encryption\Removable Data Drives\Allow access to BitLocker-protected removable data drives from earlier versions of Windows Computer Configuration\Administrative Templates\Windows Components\BitLocker Drive Encryption\Fixed Data Drives\Allow access to BitLocker-protected fixed data drives from earlier versions of Windows To allow computers running Windows Vista, Windows XP with SP3, or Windows XP with SP2 to open BitLocker-protected data drives