Just tried it, that's what you get when encoding that string:

```
ELISP> (encode-coding-string (unibyte-string 1 2 3 4 5) 'utf-8)
"^A^B^C^D^E"
```

Where each of these ^* is just one character actually.  So apparently it's just a valid sequence of control characters.  Cool… :)

Anyhow, as long as it doesn't explode, we are safe I guess ;)