I found an interesting web site which does rather highlight some of the issues with what 3 words, w3w.me.ss. Well worth a look.
Whilst it is a fun application, a novelty, I personally do not feel it has any place being promoted by emergency services. And this post is my honestly held personal opinion, as always.
If they want to "handle" w3w addresses from the public, that may make some sense, as it is popular. If the app if given to them free of charge (as seems to be the case), and if they take any w3w address with some caution, checking the location by other means if possible, then yes, fine.
But reports on social media (including from people I personally know) suggest that w3w is not just "promoted" by emergency services but actively preferred to the extent that call handles will refuse to take simple o/s grid references and insist on a w3w address. For one recent case, the police force in question confirmed that they should have taken an o/s grid reference. But in practice this seems not to be the case.
What seems worse is stories of people being talked through downloading the app on an emergency call. This is quite incomprehensible. Even if you want a w3w address for some reason, it is far quicker to send someone to the w3w web page (what3words.com) which shows your location. The only possible reason to download the app is so the user has the app on their phone. It is a purely marketing activity, as someone is more likely to use w3w if they have the app. Do we really want emergency services actively engaged in time consuming marketing activity for third party closed commercial apps, during an emergency call?
As I say, much of this is anecdotal, but social media is full of this, as highlighted by w3w.me.ss.
What is especially odd is that w3w's own terms and conditions are not consistent with use in an emergency. They expect you to read, understand, and agree many thousands of words before use, and expect you to check the terms before every use. This is not sensible for the caller, and the emergency call handling staff, to do in an emergency situation where time is critical. Also, the terms prohibit use where it could lead to someone dying, which is often the case in an emergency. Given these clear terms, it makes no sense emergency services would even be considering w3w usage, let alone promoting it. It is almost as if they did no checks at all on how it works or even just reading the terms.
There are ways to get location from callers, not just (long standing, open standard) alternatives like o/s grid references or even simple latitude/longitude, but means that don't involve any reading out, like SARLOC or AML. These should be available to emergency services. Even if there is need for a caller to give a different location, knowing where the caller is puts that in context and helps eliminate errors, whatever format is used.
So, in order to try and address this, I have made a petition. It calls for "Review how emergency services handle location data from the public." which I think is fair.