In the case of Luxembourg, just like Hong Kong until 2009, Luxembourg was not prepared to override its domestic secrecy law. As of 2009, they decided they were prepared to incorporate in their treaty exchange agreements information that would override their bank secrecy law, but only to the extent that it was information on request.
That's their treaty policy. The choice for us is, well, do we go as far as they're prepared to go, and let's see what the future holds?