Page 13 of this 2006 RYA Wavelength publication provides useful advice on kill cords and refers to the RYA producing a sticker.
Dual kill cords for kids advice is repeated in April's edition of 2013 on page 7
Further reference is made on page 5 of February 2013 issue.
My RIB has an MCA wear your kill cord sticker which was available on link below, currently out of stock. Its a triangular sticker similar to the Lifejacket useless unless worn one. It works for me as a reminder stuck on the console just above the steering wheel.
Recreation and water sport*: Publications - MCA
It's difficult to see what good can come out of such a tragedy and whilst I accept that on here it's generally preaching to the converted this discussion is a good thing and it has certainly made us all think and for me at least the sheer horror and then sadness of this incident will endure for a long time to come and go on reminding me.
It's a sad fact of life that accidents will happen and that life hangs by a thread whether you're driving a car, walking along a pontoon in the dark, or stepping out of a tender onto a boat. A momentary lapse of concentration or attention to detail is all it sometimes takes. Regulation will not necessarily interrupt a chain of events which lead to a tragedy and blame in an incident of this nature serves no useful purpose either. Even if and I repeat if there were any blame in this case the price has been paid in full.
The best we can all do is learn and as has already been commendably mentioned is to try and influence and educate where we are able.