Take a look at our vans.
If a van near bye became engulfed in fire and you were asleep your van could rapidly begin to be involved. In the dark you would have to get out of your bed, raise the bed back to the ceiling. Remove blinds from the windows. Turn the drivers seat forward, before moving the van. And all of the above newly awake in an extremely stressful situation. Also some within vans are not as ambulent.
I don’t think the 6m distance will be enforced, but it will be mandatory possibly preventing the Aire owners from litigation. This is why The forestry made this mandatory for their trial period.
Also there could be insurance issues if these rules laid down are not followed.
There’s also the possibility this could happen during the day when the vans are not occupied.
This is a difficult issue for anyone running an Aire. If they allow vans to park 3 metres apart and people died, or vans were lost they could be held responsible.
Motorised vehicles carry a high fire risk, hence why garages built within dwellings are double lined with plasterboard, and any internal access doors must give one hours fire protection.