Art, this is a serious issue. This is no different than hard drives in our computers, laptops, netbooks or anything that uses a HD. They are all storing electronic digital magnetic information. Those that have encryption are not safe if you know what you are doing. These encrypted containers can easily be tapped and opened. If you don't believe me do a little research on computer forensics.
http://en.wikipedia.org/wiki/Computer_forensics
This has been an interest of mine that is quite fascinating to explore. Did you know that if you format a hard drive that the data can still be recovered? There are wipe methods to prevent software recovery and hardware recovery. The dept. of defense has a specific 7 pass sanitize method that Sharp utilizes. That will prevent hardware recovery. However no matter where the hard drive comes from there have been documented cases of reverse engineering to bypass the wipe method. If know the wipe method used. This is why the specific methodologies are top secret and you can customize your sanitation method that is unique to prohibit this reversing process. The maximum security is 35 passes to sanitize the HD. This is based on Peter Gutmanns' paper "Secure Deletion of Data from Magnetic and Solid-State Memory". The method is designed to erase data regardless of disk raw encoding. It effectively removes the magnetic remnants from disk, preventing hardware recovery tools from restoring any data.
I knew someone that had a HD in which they took a sledge hammer to. Broke the HD platters in many chunks & pieces. Guess what? That was not enough. Data was still recovered from chunks that were encrypted.
So the best thing to do is pulvzerize your HD's to dust then you can rest assured everything is gone.
Sharp was the first to address security in digital imaging and received the first Common Criteria Validation for an MFP in 2001. Even today, Sharp remains the highest rated company for validated MFP products, and is regarded as one of the industry's greatest security innovators.