Some people will find that terrible in itself, but even if you don't, there are unintended consequences. Suppose she is out there buying you a surprise present. You catch here with the present in hand; she is disappointed that you found out about it. So, next time, she switches off the 'find me' feature. You see she switched it off, and either think 'she is trying to surprise me', in which case half the surprise is gone, or worse, 'what is she hiding?'.
Right, and if they do find it terrible, they don't use the software. It's not rocket surgery.
> "What is she hiding"?
Please, I'm not a sitcom character.
To attempt to address the apparently spirit of your concern, of course there are unintended consequences (to anything). The important question is whether the net effect is "terrible" (GP's impression), "awesome" (my experience), or somewhere in between. It seems to me that the main differentiator is what relative value you (and the close friends who would be candidates for sharing location data) put on secrecy (among those close friends) vs information (about those close friends). And I am reporting that in my life, I have yet to experience any downside, I've experienced plenty of upside, and some of the upsides have been awesome.
I would certainly be horrified and angry if Google turned this feature on by default, or if user locations were published to people they hadn't consented to, or something like that.
For the last time, privacy is not about secrecy, and it is not a battle against information. It's about dignity. It's great people get value out of these features, but do understand that to those who have not assimilated into this new culture, the idea that having to dawdle in uncertainty for 10-15 minutes while you wait for your wife to meet you downtown is some burden is ... crazy!
I thought mobile phones were supposed to solve that problem anyway. It seems nobody's content enough to agree on a meeting and patiently wait for their company anymore. Either that or they are worry-warts, or just plain distrusting. I find these new values very difficult to relate to, as I cannot imagine another reason for tracking your companion like they're a specimen of some endangered species.