Some thoughts about the /\n\b/ idea. It is very inspired, and I ++'ed it. But, it will fail in the following circumstances:

1. If you are running on Unix and your email was received on a Mac (or Windows) and copied over using Samba or something similar. (The \n will not match the line ending.)
2. If the email has a space at the beginning of a line with a key. (Mine handles this correctly, as does BrowserUk's.)
3. Be absolutely sure you know what \b matches. It is a zero-width assertion that matches the boundary between \w\W or \W\w. \w is (basically) [a-zA-Z0-9_]. So, if one of your labels starts with a quote, it won't match.

Now, if your situation avoids the above pitfalls, go right ahead. Comment it, though. If we, with large number of combined years of experience, consider it inspired, your maintenance programmer will consider it demonic and worthy of tracking you down with a bloody axe.