On the contrary, this should be extremely accurate.

Almost all large multifloor buildings rely on DAS units. Basically these are like Wifi points that broadcast the cellular signal and are spread around the building (usually a few per floor). The connect back to the carrier via fiber. The carriers usually offer to install them for free in our buildings because they take loads of traffic off of cell towers. Multistory buildings can house thousands of people so it is a big win to get them off the air. Since each repeater knows it's located exactly, it's easy to pass that data along to the PSAP.

Cisco VOIP phones can do something similar using Cisco Emergency Responder. This can give even more detail down to the office / cube number.

On Catalyst 3850s this has been fixed since the release of 3.3.5SE code (release November 2014), so this is old news. Even on older code, the problem can be fixed by using the command "no setup express". I have to say running into this the first time and trying to figure out why the switch had a blank config was a head scratcher...