I just remembered a recommendation for ALL events with transition bags or where you check post-race gear bags:
Be sure to bring a fat Sharpie to the race and write your number on ALL race bags, every time, in addition to any stickers they give you. Adding some brightly-colored duct tape on the outside also makes it much easier to spot your own bag. (Put Sharpies and duct tape on your triathlon packing list, too! I often use bright pink duct tape to highlight my rack spot as well.)
At Chesapeakeman in the downpour the stickers came off many of the bags. We volunteers wrote numbers on the outside of most of the bags that we could figure out (which often involved searching through the bag contents), but I'm sure there were a few bags that went missing!