It is mainly by actively checking if you have deleted them probably after assuming you have done so that they can find out, because not everyone knows about the methods that I mentioned above.
Let's get this straight: censoring is irreversible.
Despite the simplicity of this tool, some edits are easy to identify or spot.
But I checked a couple weeks ago and it still had the grey arrow but said opened.
Snapchat allows you to select stickers using three different tools: a brush tool, a rectangle tool, and a magic wand.
Users are always notified when you add them on Snapchat, unlike if you delete them.
This is why YouTube has one of the biggest user-bases currently, and people search for tools to easily download these files.
If you delete someone on Snapchat who is in the same Snapchat group as you, not much will happen.