It's acting as a captcha — otherwise they'd have to deal with a shitton of automated replies and bounces from the customers and their crappy mailservers

Surely it's the job description of customer service to deal with hassles in order to make users' lives easier?

Often times customer service == the development team == the marketing team == the executives == you

When you're a small shop, dealing with this kind of stuff day in, day out can get very taxing.

OK, so set up a filtration system. If you're good enough to build a system capable of running at that level you should be able to set up some basic mail filters or even a more complex bayesian filter to knock out at least bounces and probably a good percentage of autoreplies too.

Removing noise from a system isn't a job where it's perfect or useless; a substantial reduction is often quite good enough.

I don't see why it's necessary to make this complicated: "friendlyrobot" is the filtration system. As you said, it doesn't need to be perfect to be useful.

Bounces and auto-responders can be parsed and separated from human responses.

Hate to subject customers to a captcha when they need support!