For Q2 and Q3 Thuimb drives still work the same way - and differently from actual USB harddisks
Basically flash based thumb drives show up in the operating systemas removable media ( open My Computer and look at the sections the drives appear in to see this) and hence are handled in the same way as RDX cartridges (which means you may need to read documentation about RDX to understand the handling.)
USB Harddisks however seem to show up in the Operating System as Fixed Disks (for reasons that are between the OS vendors and the disk vendors) and are therefore handled slightly differently.
The handling for both types of disk has not changed since BE 2014 (it did work a little differently in BE 2012, and was completely different in BE 2010 R3 and earlier.