Sometimes I accidentally hit r instead of f in newsgroups. Can Gnus warn me, when I'm replying by mail in newsgroups?
Put this in ~/.gnus.el:
(setq gnus-confirm-mail-reply-to-news t)
if you already use Gnus 5.10, if you still use 5.8.8 or 5.9 try this instead:
(with-eval-after-load "gnus-msg" (unless (boundp 'gnus-confirm-mail-reply-to-news) (defadvice gnus-summary-reply (around reply-in-news activate) "Request confirmation when replying to news." (interactive) (when (or (not (gnus-news-group-p gnus-newsgroup-name)) (y-or-n-p "Really reply by mail to article author? ")) ad-do-it))))