With the greatest respect, not just Thailand. How many of you have seen such behavior ending in tragic accidents in your own country as the result of using a smartphone. It is not just children but adults as well!! During my travels throughout neighboring Burma, Laos, Cambodia and Vietnam, driving a vehicle whilst using a smartphone was a common sight - school kids, car drivers, lorry drivers, bus drivers, delivery drivers etc. etc. Some of the worst offenders I saw were food delivery persons on their motorbikes weaving in and out amongst traffic trying to follow a route from GPS whilst holding their smartphones. IMO smartphones are not so "smart" when they are responsible for the tragic death of a person.
RIP young lady and my sincere condolences to your family.