No one wants to injure themselves at work and when they do, their doctors will normally err on the side of caution and give them more time rather than less. For an employer, this can be frustrating and sometimes unworkable, but the employee's health must be the bottom line.
Yes, you'll get some workers, that will play the system to their advantage but in general, workers don't want to be away from work with an injury and this can be as frustrating for the employee.
In my workplace, there are very limited opportunities for light or alternative duties.
The employer has a 'Duty of Care' for their staff and this should be the underlying factor, regardless of how frustrating this is for the employer.
Your workforce is your most valuable asset, remember this when you're next considering a GRTW, as being a hindrance to rather than a tool for a safe return to work.

Kia ora Sarah
As a company we operate, on a daily basis, at least 20 small forklifts (5 tonne or less), 4large forklifts (15 - 25 tonne), three side loaders and several other heavy machines. We are a large site, and we have a lot of in-house foot traffic, all carefully managed as safely as possible. All of these machines are completing possibly thousands of tasks a day and these vehicle movements will see them crisscross the paths of many other work vehicles, during their daily use. As far as I'm aware, as one of several H & S representatives within my company, although there have been many reported vehicle incidents, i am yet to see one incident that can be traced back to the wearing of a baseball cap and there are many that wear baseball caps while operating a work vehicle, on a daily basis.
We are predominantly a factory but some of our operations are performed outside as well and I have yet to see or hear about an incident that's relatable back to the wearing of a baseball cap, this isn't to say that this hasn't happened or that it wasn't notified in the details of the incident, but until we have an incident that can be related back to the wearing of a baseball cap, then I'm not convinced that banning them has any effect on the H & S of vehicle operations. Happy to be proven wrong though.

Kia ora Chrissy

Our investigation system, relies on the input from the person whom is entering the incident on to our database. 9 times out of 10, this person is a H & S representative. When we get to the risk assessment section, the investigation will either be a 'simple' or 'full' investigation, dependant on the input. The system automatically allocates the type of investigation, dependant on the severity marking attributed to the incident.
Nga mihi
Grahame

Mr Ed

Rather than throwing legislation at him because this is going to cause a very disharmonious and potentially acrid workplace atmosphere and can then lead on to more open displays of hostility from your work colleague.
Appeal, in the first place, to his sense or any sense of social responsibilty; unsue of your familial situation but if you have a wife/partner and/or children, to go home to, then tjhis can be used as leverage to support the idea of secondary intake of his actions that could possibly affecting your own health which then has a flow on effect on your family.
Also, talk to the other three work colleagues and see if you can get their support or at least the support of one, when and if you decide to confront this person. This approach and the manner in which you deliver your message, will hopefully have a successful outcome otherwise, the rules and regulations as mentioned by previous correspondants, may and will have to suffice, but don't expect a positive outcome from this person.

Kia ora tatou

One idea which will get them more engaged (if that's what your after) and adding value to a business, is to get them running and organising a H & S Committee meeting. Due to the size of our single site business, we have three committees, with one being run/managed/organised by our h & S reps. This gives validation and ownership back to the staff and becomes more transparent. The safety reps get good hands on experience and confidence, it's one less administrative area for management to worry about and our staff feel they have more input into these meetings.

Nga mihi
Grahame Andrews

Kia ora tatou
I'm Grahame Andrews and I've been with my employer Nelson Pine Industries, for 19 years. I'm a 'Process Operator' (fancy name for what is basically an over qualified timber worker). I've been a Health & Safety rep for 17 of those 19 years and love that facet of my job. it's a frustrating but rewarding job at the same time. We are a company with three defined areas, thus we have a H & S committee, for each area. The overlap comes with our management attending all three meetings. Two of the committees meet quarterly, whilst the third meets monthly. We employ approximately 250 and are one of the bigger employers in Nelson. H & S is always a work in progress!
Nga mihi nui

Peter, we have a strict policy that unless you're expecting an emergency call or that you have prearranged with your manager, their acceptance to have their phone at or near their workstation, then phones are only for use at break times. It is not a good look when you observe someone on their phone during work hours needlessly and more so if there are visitors going through, around or near ones workstation. Initially, as there normally will be, some obvious opposition to this policy but in our case it worked well. Some of the concern was when staff were texting as they were walking, a definite H & S breach, especially as we have many moving machinery parts including forklifts.

Grahame Andrews
Elected H & S Rep
Nelson Pine Industries Limited