Not to deviate from the original topic, nor to disparage any of the points in your excellent response...

but there are other alternatives beside using 'escape characters' as a method to distinguish delimiters from message content.

YAML, for example, allows indentation.

PERL, for example, allows user-definable alternate delimiters

print q/"Hello-World"/;
print q~"Hello/World~;
print q!"Hello-/-World"!;
print q§"Hello-/-World!"§;
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True, the devil is still in there, since you still have to make sure that your 'message-space' characters are always orthogonal to your 'delimiter-space' characters. Just making the point that 1) "escape characters" (as a typographical and programming convention) *suck*; and 2)This suckage is yet another of the problems already solved by perl, and YAML and Ruby (and others, if there are any).