This doesn’t make reading Bugzilla mails harder but IMHO it clutters them with unnecessary stuff. If there is nothing to quote then people shouldn’t quote. I know that several mail clients do this TOFU stuff out of the box. I also use this behavior at my company when working with Outlook. It’s sometimes quite useful to read the whole thread if someone suddenly decides to put you on CC for whatever reason without telling you what’s going on.
But Bugzilla is not Outlook. Most people are involved in the mail communication and can read the whole history online if they like. I love the clean way of quoting supported by Bugzilla. TOFU in this case just duplicates unnecessary information. 🙁
Please! Don’t post this way in Bugzilla.