Should We Look For Our Sperm Donor?

There is a post on the Yahoo Donor Sibling Registry discussion group about a family that learned that their donor had died. They had been excited as they were making plans to meet and recently learned of his passing.

Makes you wonder, whether despite the legal contract I signed not to look, whether we should be looking. My first responsibilty is to my own kids not ethically whether I must uphold the contract. Should we look now? Just to locate him so we know where to go if the kids are interested to know. If we wait we could lose their opportunity.