Assembled Gentlefolk: Hmmm...
Well, what I have done so far is your directions, Neal. I removed autologin from Synaptic and checked. From reboot, no auto log-in still, and the /etc/x11/gdm/custom.conf still had things for auto equalling yes. So I disabled Autolog from GDM Conf and checked the Control Center while I was at it. Enable Auto Login there was unchecked already. Rebooted, no change, and /custom.conf had AutoLogin disabled still. So I did GDM Conf>Enable AutoLogin, checked that the settings in /custom.conf were enabled, and rebooted. No automatic login.
Cap'n S: I might consider a delay try-out as a last resort. Or an exorcist.