>I have noticed that an increasing number of packages (qmail and many pop
>servers) are using flock() to lock the incoming mailboxes before delivering
>new mail or deleting existing mail.

>Currently, most of the mail programs on NetBSD do "dot" locking.  Perhaps
>it is time to change this to flock() and friends?

Here's one plea/reason for `no': NFS

I am old-fashioned about some things.  Feel free to __add__ flock().
But never, ever _remove_ bellmail-style locking.   It's the only
one that works reliably  over NFS[*].   Personally, I prefer the
locking order that IDA sendmail's binmail replacement used.
but I guess

[*] NetBSD doesn't have an rpc.lockd, and the stock SunOS rpc.lockd
has  never worked reliably.