If you block someone on Snapchat, can they see unopened snaps?

Use the app "Snap History Eraser", and hope they haven't opened their Snapchat app in the meantime (or had it running when you sent the snap), because once the snap is saved on their device, they can still access it. read more

If the person you accidentally sent the snap to still has the Snapchat app running on their phone, even if you block them before they opened it, they will still receive the photo/video. The reason being, with the app still running in the background, whether they are physically on the app or not, Snapchat can still receive the data. read more