This took some head-scratching for me, but YOU CAN gain root access to the N5 and modify a configuration file (a file requiring root level access) that, now, will tell the phone it doesn’t have to mention to carriers that it is re-routing the data (which is already being paid for) to an external device that may not be able to get a WI-FI signal (laptop or tablet).

I won’t go into the specifics, unless someone asks, because it would be a long-winded story.

The Nexus 4 didn’t (and doesn’t) need this “fix”, but the distribution of KitKat for this phone needs to be told not to send on the tattle-tale message that it is trying to tether. Most of the over-$50 plans on T-Mobile now have free tethering (250MB/mo) but for the old plans it would require a $15/mo extra payment. 

The time it took was a few hours of scouring the Android developers on the Web (AKA hackers) and about $7 in apps from the Playstore. Someone more used to Android could do it in a half hour.