I would agree, A thorough RA should be carried out, just because the body is outside does not infer that the truck is unsuitable, consider stand on platform trucks for instance. You are open to the elements on one of these little trucks. Provided the management are pulling up operatives (as should you or anyone who see's someone being a numbty - remembering we are all responsible) if they are operating the trucks irresponsibly and suitably cautioned, they should be fine. Remember that a Safe System Of Work should also accompany the RA, this should say that when operatives are in positions of Risk ( Local Conditions - i.e. Aisles -pedestrian crossing walkways )- they (the operator) should act with caution and slow down, paying more attention to his/her surroundings.

You could already argue that the person is already half way out of the truck in the first instance, again a reference to this in a RA should cover this. Special attention should be applied when working near CB trucks that stacking - destacking.

You do not say wether the truck is a fully seated on or not - I would guess its the latter. You should get in an independent to view.

You should also use historical evidence to decide how much of a risk is involved, however the only proviso with this method is people always blame the truck when an incident has happened - brakes failed! is the usual culprit. It is more likely that speeding is the culprit. These ones obviously should be disregarded if any doubt arises as to its integrity. If however the brakes actually did fail, how often has it occurred? - once only is a very low risk if you account of the 24/7x365 status of your operating unit. Similarly more caution should be applied when poor weather prevails, Power Pallet Trucks are especially prone to skidding on wet floor surfaces as is any ppt/cb which has no treads (show me a warehouse that doesnt have one leak and I'll show you my 300 yr old PC!)

Another point worth considering, is that in general people are getting larger, this has the obvious ramifications of body parts overhanging the cab. Again local assessments should made.