There are no hard and fast rules to determine whether or not you can trust a merchandise store to be officially licensed by David to sell his merch. However, there are a couple of things you can do to prevent any disappointment. First of all, make sure you check out the socials of whatever influencer you wish to support; usually, they will have a link to their official merchandise store in their bio or handle. Alternatively, they may speak about this site during their videos.