Re: autoupdating mtime column

>> have a real use-case for suppressing mtime updates?
> Syncing tables between databases (a la "rsync --times"). Btw, I'm
> considering temporarily disabling the update_times() trigger when sync-ing.

I'd consider running the sync as a different (privileged) user and
checking the current user in the trigger. Ordinary users always get
now(), privileged users always get what they provide (and they are
forced to provide some value). Does what you want and adds a safety
catch too.

Alternatively, you could do something similar with views.