Hi Mark,
I do love the discounts in shopping we enjoy one of the perks of being Disney Vacation Club members!
I always carry my Disney Vacation Club member card with me when I visit Walt Disney World, as well as my drivers licence. Most often a cast member will ask to see the Disney Vacation Club member card, and I have been asked for additional identification as well to help protect against fraud. Your Key to the World Card may indicate that you are a Disney Vacation Club member; however, I've always found it easier just to have my membership card with me in case the information get printed on my Key to the World card or if there are additional questions.
Remember to check Portable Perks, available for download from the
Disney Vacation Club member website, for a list of current discounts available. Please remember that all member perks, including shopping discounts, are subject to change.
I hope that this information is helpful for you, Mark! Please do not hesitate to ask if you have any further questions.