The idea itself seems interesting, but the implementation is not.
A i see there, the copper tape is strapped directly to the wall. What happens you pour a liquid over that and then touch it? The idea is, I suppose, that this way those wires may be very thin, but i don't think its a good idea to put 230VAC there.
Those were the cons, but what if we do it properly? For example if we add a proper insulation tape below and above the copper track? This should be sufficient (see the image
https://dl.dropboxusercontent.com/u/7430474/Untitled.png ). The problem is this way it will get much thinner (maybe 3 times) so, its gonna be much harder to hide it behind a paint.
Moreover, according to a PCB trace width calculator included in KiCad, a 0,035mm x 11mm copper trace should be able to conduct 5 amps at 5meter distance with only 5.6W loss ( compared to 5 amps * 230 V=1150W its nothing) and 5 degree temperature rise. Calculations done for internal PCB trace.
I am not talking about passing any legal things. That idea is a neat hack that can be used to provide power where its required without using power cords (no go down, below your bench and count the number of power cords). It is simple and elegant. You can tape it over furniture(for example on the back of a shelf) to provide power to an equipment stored in it. I like it.