The original datum, from the SF Peninsula Daily Post for the April 30th weekend, on p. 1, printed here as a single line (rather than broken into three lines):
(1) Guard posted at crossing where woman killed
intended to convey something like
(1a) A guard has been posted at the crossing where a woman was killed
— where the omission in (1) of the underlined form of BE (in a subordinate passive clause) gave me an extended WTF? moment. Looking at parallel examples didn’t make me any happier. Maybe there are those for whom (1) and similar examples are unproblematic, but there is variation from speaker to speaker in all things, and in this case, (1) and its kin are problematic for me. Now, some background, then back to (1).