Life insurance companies require that you demonstrate insurable interest before buying a life insurance policy. The kind of life insurance you're referring to is called key persons life insurance, which allows companies to buy policies on their business partners or star employees in order to ensure smooth functioning of the business if anything happened to the partner/employee. There are several other arrangements where life insurance [MOD EDIT: Link removed.] plays a big part in a non blood-related scenario. One example is surrogate mothers, who buy additional life insurance on themselves, accept payments from the intended mother and father and lists them as beneficiaries for part of the payout in the interest of their investment, both emotional and financial, in surrogacy.
Pat Cassidy
Disclaimer: I work for AccuQuote and this is my personal opinion.