I found two posts from you and updated the document in my signature.
As soon as the MOXI connects to the Internet it sends logs about everything. If you open it, pull out the drive, clone it or whatever, then put it back, they have no way to tell. But as soon as you swap it out with another one and power with the new drive, they know. I got a not so once email stating I lost all warranty for BOTH the MOXI and the 2 Moxi Mates I have. Regardless, I am happy I did not pay them $260 + shipping and tax and swapped the old clunkier Seagate myself for a Samsung SSD. Works wonders.
Their "explanation" is that they want to return you a usable MOXI fast. So instead of keeping yours for repair & diagnostics, they just send you a refurb and take their time to work on your original. Makes sense, but I would have expected them to send out a new unit, not a refurb. Guess they are not making any new ones for some time and thats not an option anymore. And yes, if they swap the MOXI out, any shows on any external drive you may have will be lost as the new MOXI has a different encryption key.
As other have said and I tested, the best bet is a small internal HD (I used a Samsun 830 SSD) and a RAID 1 external setup (I used 2 x 4TB drives) and all seems just fine. If the internal dies, you loose very little and you can always swap out any failed external drive in the RAID 1 without any data loss.