It's both the liability issue, but also how safety incentives are set at the highest level. It is not uncommon for senior exec to get bonuses tied to lost time

It's both the liability issue, but also how safety incentives are set at the highest level. It is not uncommon for senior exec to get bonuses tied to lost time incidents, hazard reporting and other safety metrics, which get cascaded down through the org (In Australia at least). One office worker spraining an ankle on the stairs and missing a day of work muddies up the KPI's. Reinforcing the safety culture across the whole organisation between the high risk field work and office drones keeps the kpi's green, but its also an easier message to deliver to staff - everyone must play by the same rules.