Really@anon_cow
It is difficult to see the mains cables acting like anything else, since that is what they are used as.
And not only within the house but to other houses as well: In fact, to all on the same side of the mains transformer.
Practically everyone has slated PLT as a means of carrying data without interference:
" From the communications engineering perspective, power cables are about as bad as it gets. The widely varying cable impedance and imhomogenous cable mixes installed in households, commercial buildings and industrial plants result in a transmission environment which exhibits enormous variations in impedance characteristics.
This variability in cable impedance is further exacerbated by the widely differing high frequency behaviour of distribution panels, connectors, wall sockets, switches and other items of distribution hardware. Unlike hardware designed for RF or high speed applications, power hardware is optimised for robustness, low cost and low flammability. As a result, the impedance behaviour of such hardware is generally undefined. As wiring connections into such hardware do not impose impedance constraints, arbitrary birdsnests of connections are possible with the inevitable impact on impedance behaviour."
http://www.csse.monash.edu.au/~carlo/SYSTEMS/Powerline-Networks-0602.htm
"a) The cumulative noise field strength due to the PLT emissions may have a possible detrimental effect upon military HF radio communications and COMINT systems. This is particularly the case if In-House PLT systems should become widely popular. However, it should be noted here that the determination of the nature and the severity of any possible detrimental effect upon the military systems was outside the RTG’s expertise and ToR.
b) The HF noise level in the vicinity of PLT installations has been considered in numerous other studies.
One study concludes that interference from PLT to a station receiving low-level signals is likely at distances up to 460 m from a single Access PLT installation using overhead power lines. On the other hand, in sensitive receiver sites, the user generally can be assumed to have control over the vicinities, such that a protection radius of up to 1 km, without PLT installations, can be employed. In this case, the cumulative effect of long-distance propagation from a large number of PLT installations may be a more serious problem that requires careful consideration. Therefore, the RTG chose to focus on this less-studied problem"
The above from a NATO document.
Do I care ?
Yes. PLT makes low-strength signals on 20 metres impossible to hear, and even strong signals are unpleasant to listen to.
Fortunately, the plt devices seem unable to handle strong rf signals on other bands: 80 metres ssb kills them.
Mind you, on another tack: BT has installed loads of their units (wifi) in the area...and all on channel 11.....six in the same street.....I understand they ain't workin' too well....