[legooolas]

This is possible, but requires different wiring to light switches, to provide power there (which isn't common) and for manufacturers of replacement switches, bulbs etc to care about security.

The former isn't something which is happening yet anywhere that I know of (in the UK at least, even in new-build houses), and the latter needs pressure from consumers which isn't happening for anything in the internet-of-things space yet :/

(edit: don't try to use markdown in HN comments, however automatic it has become for you :)

[lucaspiller]

I think the wiring issue is mainly a UK thing. The standard way of wiring light switches in the UK is live and neutral go to the ceiling rose, and then another two wires goes to the switch which joins the live when on. This reduces the amount of wire needed, which stems back to after WWII when copper was in short supply.

I've just bought an apartment in mainland Europe and the live and neutral go to the switch, and from there two wires go to the rose.

[bonzini]

Italy also uses live and neutral to the ceiling, with the switch joining the live.

[CapitalistCartr]

This is also the standard way in the USA. Its called a switch leg.

[quesera]

I've only seen that in older buildings in the US.

In new buildings (~1970+) I've always seen what I consider the standard: live hot and neutral to the switch. Hot is switched to the fixture, and neutrals from both sides are tied together in the box.