Reccomendations/guidelines for axis order?

[aaime]

Should the specification give recommendations on axis order, while leaving implementers free to use the axis order they prefer?
Would the order have to be fixed, so that all outputs requested in, say, "http://www.opengis.net/def/crs/EPSG/0/4269" (NAD83), share the same order (ask the same, get the same)?
However, by experience, the "useful" axis order is linked to the chosen output format, shapefiles hardly work in practice when returned in north/east order for example.

[cportele]

In general, the axis order is fixed by the CRS definition. Where necessary, a conformance class for an encoding can state different rules based on the practices of the encoding.

So, for the GeoJSON and GML conformance classes the CRS definition applies.

For a shapefile extension, one could specify a different rule for the axis order.

This would also apply in the other case. Say, we have a format the requires latitude/longitude. An extension for that encoding would have to specify that the response uses lat/long even for CRS84.