The issue is that as you and others use powerline ethernet, you leak electromagnetic interference patterns back into the powerlines. This buildup of interference from multiple homes creates problems around your area, even if you don't notice it yourself.
Except unless you have some sort of an impedance follower you'll probably just end up attenuating your powerline networking to the point of not working.
Most of the useful signal in the system is going directly from one circuit to another. The signal headed out toward the power meter is mostly dead, and you might even improve the networking by getting rid of those extra echoes.