Snapchat alerts users that the person on the other end has saved a screenshot, so as long as you don't see that, most people would assume that it has, in fact, disappeared.
Is that for Android only? Yesterday my friend and I tried it (I have an iPhone, he has a Samsung), because I was curious if I will be able to take a screenshot while holding my finger on the image and it worked. He received no notification about the screenshot, though.
Nope, my iPhone has told me when another iPhone user has saved a screenshot before. Unsure about Android/iPhone.
grey-area is referencing the analog hole, which is completely undetectable and unpreventable.
Right. I'm saying that I don't think laymen think about the analog hole; they just see that feature and assume that it actually does disappear.