I know next to nothing about the microlight world but this crash was either in VMC or in IMC.
In between the two is flight in poor vis.
People do fly into terrain in VMC but it is fairly rare, and they won't be setting 7700 when they realise the hill they turned towards is too close. An ELT which auto-activates is the best option.
Traditional CFITs are normally in IMC and the above again applies. The fact that flight in IMC, or even sub-3k vis, is technically illegal is another thing.