Thanks a lot for the example, Markus.
No quotes will be added, as your delimiter does not occur in the text value. The result can successfully be imported in spreadsheet applications without quotes.
The quotes will be added if the delimiter occurs in the texts:
declare option output:method 'csv'; declare option output:csv 'header=yes, quotes=yes, separator=|'; <csv> <record> <one>a b</one> <two>c|d</two> </record> </csv>
… yields …
one|two a b|"c|d"
Hope this helps, Christian