a completely out-of-the-blue question

Pretty much as per yesterday, except that I sleep a little less and today’s errand is to get a graphics tablet for myself so that I can do some work. Spend a while weighing up the relative merits of the different tablets. When I eventually buy one, am thrown (as usual) by the shop assistant asking a completely out-of-the-blue question, in this case whether I want to register for a loyalty card.
I find in cases such as these that the word “turistu” comes in very handy.