Goodness Gracious me! It is so! Anyone islands hopping in the U.K. and certainly, Scotland, requires picture I.D. which may be requested when arriving at the ports. This is a grandiose name for the quay sides of all the little harbours from which many of the small and medium ferries ply their transport trade.
It raises interesting scenarios. Some islands are served by small ferries and not everyday. There are times when mums in labour are hurried to hospitals on the mainland for particular maternity services. Would a mum who travelled with a bump, be allowed to make the return journey and gain access to her home island, with a little person not yet in possession of formal picture identification? 
The little offshore islands do not have sophisticated checking equipment,like airports; this creep of I.D. is no doubt, kidology. It could be seen that one of the main uses of photo I.D. in these circumstances, would be to check a printed name against a manifest. Those who have booked well in advance will be on that type of listing. Car passengers, in general, are. Many foot passengers are not.
Oh what a tangled web we weave .......and what a mish mash. 
technomist
Its all hockum.