Is this a case of most Web servers catching and correcting for this, or most browsers being smart enough to handle this? I suspect the former.

And you'd be right. It pays occasionally to remember that CGI/1.x != HTTP/1.x. The data protocol a CGI script uses to send data to the web server may look like HTTP, but it's CGI. The web server should parse the script's output per the CGI specification, not HTTP, and then issue to the browser a properly-formatted HTTP response.

The real question is: Does the CGI specification mandate any specific style of newline? Beats me, but the web server (Apache in my case) seems to like any type of newline I give it.

It always generates HTTP newlines as \cM\cJ, though.