The traditional use of a scratch & win campaign is similar to a surprise and delight by rewarding customers for making a purchase and scanning the QR code after they have purchased.
You can set up a scratch & win to be centre-wide or for a category or specific retailer. A customer makes a purchase in a participating retail store and scans the QR code after they have purchased to accrue purchase points. After they scan the qr code of the participating retailer, a digital scratch card will appear. They will then receive a surprise and delight or a 'try again' message.
For centres wanting to drive food retailer engagement, a 'Dine in to Win' could be implemented. Make it a scratch card that triggers for dine-in customers to win an instant reward/enter major comp, or a food voucher than encourages return visitation rewarding their behaviour. Or for non-foodies - Check in to win. To drive visitation to centre/stores. Alternatively, this same mechanic can be a good cross-category promotion (specialty offers to dine in customers; food offers for specialty customers).