I believe it is an "after failure" campaign, primarily because the vast majority of X5s don't have a problem. There are enough examples that BMW has a fix (heated/insulated breather lines) when required.

If someone has an example of a broad recall for unaffected vehicles, please chime in.

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue