[dwroberts]

Some of the rules seem very arbitrary too

> Must: Represent tags as strings

Provided the correct result is generated I don't get the rationale for this one. As long as you obey the other rule for UTF-8 compatibility, why would it be a problem to represent as bytes (or anything else)?

Seems like it would put e.g. GC'ed languages where strings are immutable at a big disadvantage