[ruby-core:25829] string objects don't survive round-trip in yaml&json

It appears that strings containing just newlines don't emerge the same
after a round-trip thru yaml. This appears to be the case in all
versions of ruby's yaml library. I think it's been around forever; I
vaguely remember running across this when I first started fooling with
yaml. Confirmed for sure in 1.9.2dev, 1.9.1, and 1.8.6. I expect the
output of all 3 of the following commands to be "\n", not an empty string:

$ ruby-snapshot -v -ryaml -e 'p YAML.load YAML.dump "\n"'
ruby 1.9.2dev (2009-09-28 trunk 25126) [i686-linux]
""

$ ruby191 -v -ryaml -e 'p YAML.load YAML.dump "\n"'
ruby 1.9.1p129 (2009-05-12 revision 23412) [i686-linux]
""

$ ruby186 -v -ryaml -e 'p YAML.load YAML.dump "\n"'
ruby 1.8.6 (2009-06-08 patchlevel 369) [i686-linux]
-e:1: warning: parenthesize argument(s) for future version
-e:1: warning: parenthesize argument(s) for future version
""



Json has trouble with string round-trips too; it crashes when parsing
any string if at the root of the object tree to be dumped+restored.
Observed in both 1.9.2dev and 1.9.1 (and 1.8.6 with json gem installed).

$ ruby191 -v -rjson -e 'p JSON.parse JSON.unparse "foobar"'
ruby 1.9.1p129 (2009-05-12 revision 23412) [i686-linux]
json/common.rb:274: warning: method redefined; discarding old recurse_proc
json/common.rb:122:in `parse': 574: unexpected token at '"foobar"'
(JSON::ParserError)
	from json/common.rb:122:in `parse'
	from -e:1:in `<main>'

$ ruby -v -rjson -e 'p JSON.parse JSON.unparse "foobar"'
ruby 1.9.2dev (2009-09-28 trunk 25126) [i686-linux]
json/common.rb:273: warning: method redefined; discarding old recurse_proc
json/common.rb:122:in `parse': 618: unexpected token at '"foobar"'
(JSON::ParserError)
	from json/common.rb:122:in `parse'
	from -e:1:in `<main>'


Note that simply enclosing the string in an array makes the problem
disappear:

$ ruby191 -v -rjson -e 'p JSON.parse JSON.unparse ["foobar"]'
ruby 1.9.1p129 (2009-05-12 revision 23412) [i686-linux]
json/common.rb:274: warning: method redefined; discarding old recurse_proc
["foobar"]

(Some overlong lines in console output have been shortened in hopes of
preventing ugly wrapping.)

I'm pretty sure these are both bugs, but I may be missing something.
Before I go ahead and report them, does anyone know a reason why they
shouldn't be considered bugs?