Maybe this feature already exists, and I never saw it mentioned anywhere. When somebody goes on vacation, they often set a vacation auto-reply to let people know that their message won’t be read until the vacation ends. Some people think this is good etiquette; some think it’s bad. Some employers require it; others forbid it. Anyway, let’s say that you work in a place where a lot of your email is automatically generated, such as by bug trackers or source-control systems. It seems such a waste for my mailer to attempt a vacation auto-reply which will just go into a black hole somewhere. Wouldn’t it be better to prevent such an auto-reply from being generated? Something like this:

X-Allow-Auto-Reply: no

I know there are some headers, like List-Xxx, that can indicate mail is from a list and give a pretty strong hint that an auto-reply would be pointless, but that’s not quite the same thing. Not all auto-generated mail is generated by a list manager or destined for a list, for one thing. For another, I’m sure many people would like to have their mail program insert such a header into every email they send even though they’d be perfectly capable of receiving a reply. Surely I’m not the only person to have noticed this easy-to-eliminate waste, but there doesn’t seem to be any well publicized solution. Can anyone point me to one that might actually be implemented somewhere?