I am currently working on a new backup service for all of my clients, where every day an automated system will take a copy of all of the website files, as well as a copy of the database. This will then be zipped and sent to a cloud storage server such as DigitalOcean, Amazon etc, all under one account which would be owned and paid for by me/my business.
These backups can't be viewed or edited by the client, they are just used to restore a site to a previous state if something goes wrong. The client has access to a control panel on my website where they can click to restore a backup, but they don't have direct access to the files of the backup or the cloud storage itself.
If for whatever reason, one of my clients websites contained illegal images or copyrighted material and the cloud storage system detected this, would I/my business be legally responsible or accountable for them?
If I am, does this mean I'm expected to develop a system that detects these type of files, if so, what if my system fails to detect these files and the cloud storage system doesn't, is that also my fault?
Is there a way that I could explain my system to the law if I was questioned about it, that it's merely backing up my clients website and we don't know what the files contain? I feel like that's not good enough grounds as a defence.
Is there a required practice that I'm unaware of for companies that offer a backup services?
I basically don't want to get screwed over because one of my clients is an idiot.