unrecognized custom parameter and optional parameters responses

[molinaro-m]

ConeSearch states (end of §2.1)

If a query includes an optional parameter, either one specified by this document or not, that is not supported by the service implementation, the service must ignore that parameter.

This looks like silent failure.
Maybe we can suggest (a SHOULD?) to add <INFO> elements reporting the unused parameters.

[Zarquan]

Quietly ignoring an unknown parameter and not reporting it is a recipe for a really bad end user experience. What if it is a known parameter but the user misspills it ? If this query is part of a larger workflow it could take hours to track it down.

Good software should fail early and fail loudly.