What distribution is that, or did you build KDE from source yourself? What mountpoint do these drives get?
I can recall that with my KUbuntu 14.04 desktop I have set up /etc/fstab entries for certain external media (using the "user" or even uid mount options, but I don't think that was for generic FAT-formatted thumb drives. IOW, I think everything worked fine for the needs of the average Joe or Jane User and I had to do the usual fstab tweaking only when I had special needs. R.
