As an addendum to the previous post, I am going to clarify why securing the Imported Items is likely outside of AC's "jurisdiction". There's a good chance most users rely on sharing other folders outside of AC, maybe a spreadsheet or scans or faxes. It would logically follow that you would need to secure those shares in the same manner as the AC folder. It becomes apparent as to why they didn't encrypt the files. There needs to be a global change with respect to network security rather than a local one just for AC. If AC does encrypt the files, that doesn't help the other shares that you maybe using.
Also, there's a more technical reason as to why it would be a waste of time. There are people

that can take a copy of the database and mount in SQL and pull all the data without needing to know any of your passwords. There are also built in back door accounts for administration created by Amazing Charts. For example, if AC or a partnered developer (e.g. UpDox) had a leak and the sa or one of the other built-in passwords was exposed, everyone would be at risk. So a global security policy would be more effective and sustainable solution regardless of the software used.