To help "sell" the theme of a real street, Imagineers included many elements of theme to make Sunset Boulevard look like a real street from the real world. Imagineers included obvious things like painting the street with traffic lines, lamps and benches. They also included more subtle touches that were authentic to the time period that the street was meant to recall. Included among these touches are a number of bags of luggage that are often overlooked, especially the details on the bags.
On the bags themself are stickers for locations that whoever owns the bags has been to. Early in the 20th century, it was common for travellers to put stickers of the locations they'd been as a small momento to remember the trips. Imagineers added stickers from many locations, but Disney Imagineers couldn't resist plugging their own product. Included with stickers for the Canadian Rockies and Alaska are stickers for the Disney Vacation Club properties.
There are stickers for a few Disney Vacation Club resorts such as Old Key West and Hilton Head Island resorts. It's a very sublte plug the Disney Vacation Club program and it's doubtful anyone has signed up for a tour or bought into DVC because of these stickers, but Disney likes to promote itself (if it can) and these are probably overlooked by many guests but those who pay careful attention, will notice this inside joke.