Not sure whether this is intentional or not but mapping a network path to a drive letter and adding the drive letter (or one of its subdirs) as a watched folder does not trigger a scan.
Reverting to \ipaddress\folder works. Having said that \ipaddress\folder has two subfolders, one filled with music and the other empty. Pointing it to \ipaddress\folder causes it to watch the folder without scanning whereas pointing it to \ipaddress\folder\foldercontainingalbums triggers an import.
This works for me. I have network drives mapped to drive letters on my Roon core and it works/watches the folders just fine as if they were local drives.