IMHO it's not unquoted list are more dangerous than an unquoted scalar value but rather anything more complicated than a single identifier is potentially dangerous.

Sure you can argue about that, but I somehow like the symmetry between $hash{...} autoquoting one key  ... => $value autoquoting one key.

Still it's an arbitrary distinction, and in the Perl 6 design that was avoided by adding another quoting construct: %hash{mykey} never autoquotes, but interprets mykey is a function call, whereas %hash<mykey> explicitly quotes, and is extensible to lists: %hash<key1 key2>.

The same construct can also be used in "normal" (non-postcircumfix) Perl 6 code: my @array = <word1 word2>;