Thunar should support refreshing to show the user recent changes made to the directory. It would also be nice to hit ctrl+r and/or F5 to force this refresh as well.
Thunar monitors the underlying file system using either Gamin or FAM (if you don't build with support for either of them, Thunar won't be informed about changes to the filesystem done by other applications). The current development version also includes an explicit "Reload" action (Ctrl+R and F5 are both supported).