The other day we were having coffee in a sidewalk cafe, and there was a signal of a storm. It came to nothing. "A false alarm," I said to my friend. "Gricean analysis needed" I thought to myself. It seems people misuse the expression, 'true alarm'. Indeed, they hardly use it, but if they would, they would misuse it. For Grice, 'mean' can be 'natural', as in: ------ Those black clouds mean rain. or 'non-natural', as in: ------ Her crocodile tears. ------ Similarly, alarms, I hold, alla Peirce, can be _false_ (the well-known ones) or 'true'. The first use of 'sema' (Greek for 'sign') in Herodotus relates to that. I would say that if black clouds MEAN-n (or indicate) rain, YET there is no rain, a true alarm was a mere implicature. In Grice's idiolect, ------ Those clouds meant rain, but there was no rain. is a contradiction. To me, it is what I call a Griceo-contradiction, via implicature, not entailment. Cheers. Speranza, Bordighera, etc.