On Snapchat does it for sure mean that someone saw something that I sent if there was a red outlined box by their name? Because I accidentally took a picture or a video or something with the volume button and then I pushed the back arrow so I don't think it sent but then there was a red outlined box by someone's name and it was not there before that so did they see what I thought I did not send? Does a red outlined box mean they saw something for sure?