> How much are these customers paying for support to have Raymond Chen on first level support to debug their batch files?

Or rather, maybe, how bad are the initial support levels that couldn't figure out basic functionality like this and it was escalated to Chen?

Or maybe he was on a project working directly with the client already, so this was just part of whatever he was working on.

I was an engineer on the Visual Studio team. Many of the issues I worked on were things I found interesting. I wouldn't be surprised if Chen was browsing through open tickets, found this one, and grabbed it.

Senior people like Raymond Chen (or at least the good ones) often get to where they are by doing some amount of work that's "below them" or outside their scope in order to keep their understanding of the full stack up to date.

It wouldn't surprise me if he's periodically snooping the lowest level support queues from time to time to understand what kinds of issues customers face, where the pain points are, etc, etc.