One of the experts from Swisstopo responded recently after I gave him the hint that OSM is doing a comparison.
He answered:
<<
Die Schreibweisen im GWR haben m.E. eine sehr gute Qualittät. (...).
Gerade aber beim Ae, Oe, Ue resp. Ä, Ö, Ü existiert heute kein Standard ausser, dass man pro Gemeinde einheitlich schreibt.
Ich habe das Wiki durch folgende Erläuterungen ergänzt: [1].
Wichtig scheint mir auch, dass man in OSM die Version verwendet Ae/OE/Ue resp. Ä Ö Ü, welche offiziell ist (d.h. die Schrweibweise von GWR zu verweden, würde ich immer empfehlen).
It may be very well regulated, but that doesn't stop people from
making mistakes.
An (non-name) example: http://qa.poole.ch/ch-roads/AG/4001.html
There are three obviously wrong PLZ6 values (this is actually a
surprise since it would be easy to catch these automatically). I
suspect these are simple typos during data entry, it is unreasonable
to expect it to be different with names. If we suspect a real error,
best would to check with the municipality in question since they did
the data entry in the first place.
Simon
Am 11.11.2012 23:36, schrieb Stefan
Keller:
Dear all
The designation of geographic place names is very well
regulated. Although there are sometimes deviations for
historical and other reasons. And there are even lively
discussions between historicians, linguists and others.
The street signs on both ends of the street are showing
"Hessengüetlistrasse".
The near hotel is named 'Hotel Hessengüetli' and is in the
'Im Hessengüetli' street.
Is this a typo in the offical Data? Should I tag it with
official_name=Hessengütlistrasse ?