Here is my take. The cavalier early days of quick build ethos are long gone. Health and safety is taken seriously and policed by experienced (often officious) people.
In the UK for some reason the usual regulations applied to commercial operations do not apply so there is no official accident investigation. I have heard of serious accident resulting in hospitalisation and months off work without official come back.
Another factor is the fact that WT org does not insure the sites or work or rather they self insure. This means there is no insurance investigation either. The people I know that have been injured have not received any compensation. Trying to claim from WT is like getting blood from a stone.