I know something similar has been mentioned (thought of this last night) but this is what you do:
Buy a couple of 5cm x 10cm cardboard cards (coloured) and do a type of treasure hunt but instead of just walking around you take your partner to the shopping center. Each shop has a specific lot/store number which you can look up on the directory.
On the first card, place a riddle/poem (this may irritate some especially those who don't generally like games). The first clue leads them into a shop and prior to them going there you have the store person hold an item under the counter for them. Say in the poem something like:
Your first location is store 2-0-8
Take your time but don't be late.
State your name to the worker.
Obtain your next clue and proceed further.
And so on, leading to different stores collecting different gifts. Then eventually to some eatery or park. (Of course you have to be careful, don't make it too hard or they'll get stuck
)
Another idea is instead of making a large photograph, some places actually offer "puzzles",. They take your picture and make it into a 1000 piece jigsaw puzzle.