Yup. the folder sharing enabled through guest addons.

I didn't want to start opening shares on my notebook just to mount the flashdrive. With folder sharing, one gets the same affect as a mounted network share without opening your host up further (if you've not yet had reason for samba shares); no login credentials sprayed across the network, no opportunity to MITM the traffic, no involving unnecessary components, no modifying firewall rules. If my host OS was a Windows box though, I may have gone with a samba share instead. With both OS, it would mean modifying firewall rules though. No thinking about it, the firewall rules could be a pain; I either open them up wider than wanted to accomodate guests on dynamic IP ranges or I deal with guests on static IP which change depending on what network I'm under. Folder sharing takes that whole issue out of the picture since it's working inside the VM environment rather than looping through an external variable medium.

Whichever works though; I'm happy to have both options available.