[quote=@Caits]
It's not the fact that it's GM. It's the fact that, yes, there are lacrima planted around the town for protection and survaliance.

I wouldn't consider it OP.

I would consider it using what is at ones finger tips. 

And of course, you forget that an inn has an inn keeper. And pretty much every inn keeper has a communication lacrima to the guild. Which has been pointed out before.
[/quote]

I'm new here.  Anyway, that is an acceptable explanation.  I had assumed it was a power, not a physical system.