Well, now I have learned that explicitly setting the :unix layer is, depending on the situation, either evil or useless, I have to say that I indeed found a case where it seems to work in the way I originally intended: When it comes to creating a file, and we leave out the possibilities I mentioned, and the ones you added, and write it in the :unix layer way, i.e.

use strict;
use warnings;
open(my $fh,'>:unix','abc.txt') or die $!; 
print $fh "one line\n"
[download]

use strict;
use warnings;
open(my $fh,'>:unix','abc.txt') or die $!; 
print $fh "one line\n"
close $fh;
# No error message on unlink
unlink 'abc.txt' or die $!;
[download]

use strict;
use warnings;
open(my $fh,'>','abc.txt') or die $!; 
binmode($fh,':unix');
print $fh "one line\n"
close $fh;
# Error message on unlink
unlink 'abc.txt' or die $!;
[download]