Expect a lot of very badly designed down to cost electronics, and strange EMC problems though. If there are to be regulations they need to be backed up by a requirement for emissions and immunity testing that would allow co-siting - it is not that long ago that I was being told about  a case in some very expensive London refurbishment where the taps ran whenever the automatic lights came on - the two systems shared a mains DB and the impulse from the lighting inrush was enough to dip the mains for a few microseconds, fooling the tap sensor electronics into registering hands in front when there were none.

The other related consideration is to make sure it fails safely when it goes wrong - if after a thunderstorm you cannot stop the loos flushing, or the reverse and all your water gets off for every  power cut, then it is going to be quite fun.

It is not at all insurmountable to have robust systems, rigorous testing and provision for a manual bypass of course,  but that adds to the cost,  and there is more to it than some makers of prefab kit seem to realise - look at the difficulty of getting proof of EMC compliance testing out of manufacturers of car chargers, and then imagine what it would be like for more complex systems, and the quality of some plumber's electrics is odd enough as it is.

Expect a lot of very badly designed down to cost electronics, and strange EMC problems though. If there are to be regulations they need to be backed up by a requirement for emissions and immunity testing that would allow co-siting - it is not that long ago that I was being told about  a case in some very expensive London refurbishment where the taps ran whenever the automatic lights came on - the two systems shared a mains DB and the impulse from the lighting inrush was enough to dip the mains for a few microseconds, fooling the tap sensor electronics into registering hands in front when there were none.

The other related consideration is to make sure it fails safely when it goes wrong - if after a thunderstorm you cannot stop the loos flushing, or the reverse and all your water gets off for every  power cut, then it is going to be quite fun.

It is not at all insurmountable to have robust systems, rigorous testing and provision for a manual bypass of course,  but that adds to the cost,  and there is more to it than some makers of prefab kit seem to realise - look at the difficulty of getting proof of EMC compliance testing out of manufacturers of car chargers, and then imagine what it would be like for more complex systems, and the quality of some plumber's electrics is odd enough as it is.