It’s the nut behind the bolt in most cases as there are some very responsible drone pilots around. Considering the cost of the average drone off the shelf, most purchasers should be able to afford some training on how to use the thing before they fly it.
I know CASA are in the process of tightening up the training requirements for the issue of a RePL, however that won’t address the issue of cashed up idiots who have absolutely no respect for others purchasing drones off the shelf for recreational purposes.
Better education and very heavy penalties for the idiots may help, however that certainly won’t stop the problem.