Why don't lawmakers disclose nonprofits and charities they are affiliated with?

Sunlight Foundation:
"Last year the New York Times ran an article on the corporate donations to charities associated with members of Congress. The article showed that corporate and lobbyist donations are able to flow in unlimited sums to the favored causes of specific lawmakers, including to charities bearing the name of the lawmaker. This provides another conduit for influence seeking that falls outside of this normally regulated and disclosed realm. It seems odd that members of Congress do not have to disclose on their financial disclosure reports the non-profits and charities that they are associated with.

Only three of the twenty-one lawmakers mentioned in the New York Times article actually disclosed their association with the charity or non-profit affiliated with them. A further search of contribution records found another six lawmaker affiliated nonprofits, none of which were disclosed by the affiliated lawmaker. This may be due to an oversight in financial disclosure reporting rules."