Comments containing more than one @lert are blocked now unless they contain a backtick. In principle this is a good idea: it educates unexperienced users, while experienced users still have a workaround.
However, the comment is also blocked if it contains both "@postowner" and "@othercommenter". Funnily, this clashes with the recent change that "@postowner, @othercommenter" will in fact notify both users (see #8 of How do comment @replies work?). I simply see no reason why such comments are blocked – can they please be accepted again, even if they don't contain backticks?
The blocking algorithm should also ignore invalid @lerts like "@all" or "@lert", which are obviously not meant to notify anyone (unless the users all and lert are commenting). Same for @lerts in links: "see How do comment @replies work?" shouldn't trigger the block.
Let me also note: even for experienced users, the
` workaround is rather obscure. I'd like it better if the popup saying "Only one additional @user can be notified; the post owner will always be notified" would contain some "I know what I'm doing, submit the comment nonetheless".
Alternative idea: Make it so that two trailing spaces override the comment blocking (instead of the backtick). Then in the popup say something like "use two trailing spaces to override". This would have the advantage that people will have to read the popup (yuck!).
Jeff requested to see some real world examples, so here are a few examples of comments that shouldn't be blocked:
The OP asks about accepting an answer. Another user claims in a comment that questions without accepted answers are bumped by the community user and advises the OP to wait with accepting:
@user: No, a question will get bumped only if it has no upvoted answers. (So that shouldn't keep you from accepting an answer, @OP.)
(I know, I could omit the
OP, but the
@is a good eye-catcher.)
Replying to a user who asks about comment @replies:
@user: See How do comment @replies work? for details.
Referring to another comment in the same thread:
@user: Blah blah blah ..., see also my comment @otheruser above.
All these don't occur often, but sometimes it's very useful to post such comments.