For lack of a better place to record this peculiar behaviour, here goes:

on evp3 today, I wanted to use the auto mounter, but found there was no /etc/auto.master, despite autofs being installed (and running).  rpm -V does NOT complain about this, and reinstalling autofs did not restore the file...  This makes no sense to me.  I even tried rebuilding the rpm database (a desperate act) without any change in the behaviour.  The conundrum can be seen quite simply:

[root@evp3 ~]# ls -l /etc/auto.master
ls: cannot access /etc/auto.master: No such file or directory
[root@evp3 ~]# rpm -qf /etc/auto.master
autofs-5.0.5-88.el6.x86_64
[root@evp3 ~]# rpm -V autofs
[root@evp3 ~]#

Stumped by this, I copied a standard /etc/auto.master over from another host and proceeded with my work, but have to wonder what's going on here.