Minor Malorum Duorum

Any of y'all Virginians probably already know this, but apparently they've been selling scratcher tickets for which the top prizes have already been won. This brings up an interesting question... this is obviously always a possibility, unless you're buying the first tickets in that series. Does the purchaser need to do their homework to find out if the prizes have already been won, before buying a ticket? Or does the retailer have any responsibility to communicate that? How WOULD you know? The verification process takes time, and is sometimes not publicized until later.