The RDP Host is a Windows 10 Professional workstation, The RDP Client has USB Devices redirected and is a Windows 10 Professional workstation with a little Epson Perfection V300 Photo scanner attached via USB. No software installed. Just the driver. When I log in to the Host there is no sign of a scanner. No question marks in Device Manager. Nothing in Devices and Printers.
Interestingly enough a little Logitech Webcam (USB) does get redirected and I can see it in Device Manager on the Host. Just no sign of the scanner.