People living in Scotland are at risk of too little vitamin D, especially during the winter months, especially if they are fair skinned or if they wear clothing which restricts sunlight (burqas etc).
I agree that overdose is a risk. I'm not suggesting mega dosing with vitamin supplements. I'm suggesting that a few people (the few people who don't have access to 15 mins bright sunlight per day) would benefit from Vitamin D supplements.
Fair skin helps absorb vitamin D. But people with fair skin are warned more heavily about sunburn, and they tend to cover up and use sun block.
But you're right, I should have been clearer. People in Scotland (where the sun is only strong enough between April and September) with dark skin are also at risk of not enough vitamin D.
I doubt that there a populated places in the world without 15 min sunlight a day.