I was shocked by that post. In that case it should be reported to Sr Management and WSIB (who would have handled the company's claim for the worker that did get injured). If WSIB catches wind that the company knew about this risk (valet rage) through formal/informal complaints and chose to do nothing about it .... the premiums for their mandatory insurance would likely become astronomical to a point where it would affect company financial performance.
HR's job is to resolve problems as cheaply as possible for the company. BS is cheaper than real action.
They keep their jobs by working the system.
The union's job is to protect the workforce, not the individual worker. Same BS.