$ perl -le'print "\x{00A0}" =~ /[^\S \n]/ ?1:0;'
0  # Expected

$ perl -E'say "\x{00A0}" =~ /[^\S \n]/ ?1:0;'
0  # Feature unicode_strings doesn't fix regexes yet.

$ perl -le'print "\N{U+00A0}" =~ /[^\S \n]/ ?1:0;'
0  # Surprised!

$ perl -le'print "\x{2660}\x{00A0}" =~ /[^\S \n]/ ?1:0;'
0  # Surprised!