Changing the mark_encrypted value in the ini, saving, and then typing in a previously encrypted query resulted in a loss of encryption. I am going to look into this further as I wasn't the one who experienced this issue, however I was in conversation with them while it happened and witnessed it.
Sounds like blow.ini had already been open in the editor before the key was written. Then, on saving the mark_encrypted change, the file got reverted to the state before the key was added.
Changing the mark_encrypted value in the ini, saving, and then typing in a previously encrypted query resulted in a loss of encryption. I am going to look into this further as I wasn't the one who experienced this issue, however I was in conversation with them while it happened and witnessed it.