Kooka/xsane only see scanner as root

[Jonathan Byrne <jonathan@yamame.org>]

I'm running Sid, 2.6.8-1 kernel.  I don't often use my scanner,
and today was the first time since I moved to the 2.6 kernel.

Running as root, scanimage -L correctly shows:

device `epson:libusb:002:004' is a Epson GT-8200 flatbed scanner

sane-find-scanner correctly shows:

found USB scanner (vendor=0x04b8 [EPSON], product=0x0110 [EPSON Scanner]) at libusb:002:004

However, if I run either of those as my regular userid, they find
nothing.  So, of course, do kooka and xsane.  If I run them with
sudo, everything works fine.

This certainly smells like a permissions problem, but for the life
of me, I can't figure out with what.  /dev/usb/scanner* are owned
by root.root but are world readable/writeable, so it must be
somewhere else.

Thanks in advance for any ideas,

Jonathan