I am not sure about the second part. This is not a regular text, it's a bunch of characters. It can be put in a square (with fixed width font) so that it is obvious it is intended to be scanned. Also you usually need to actively engage the scan functionality. No way to accidently scan anything.

I am also thinking about using some identicon logic to put some color scheme on the characters themselves, so that human comparison can become very easy.