On a roll, having fixed the slow-printing problem earlier, I have now bitten the bullet and finally gotten around to locking our wireless network too. It was easier than I feared, and I only had to tell the wireless Macs the same thing. (The wired-in ones, I didn't, natch.)
Of all the wireless networks my Macs can detect out there, mine is the one with the strongest signal - by a factor of, er, double. And mine is the only router not supplied by the national telephone company.
Way to Go! One more pesky IT problem fixed, and I'll have a hat-trick!
WELL DONE BENSHEIM <---- I thought I'd put that in case no-one else does.