Can One Insured Sue Another under General Liability?
A common contractual requirement for a contractor is to remove the cross-liability exclusion under a 
General Liability policy. This exclusion deals with whether or not one insured can sue another insured.
Under older versions of ISO policy forms, such a request made perfect sense. However, under the more modern ISO policy forms, there is no endorsement to provide cross liability coverage. The reason is because there is no longer a cross liability exclusion under the policy as such coverage has been automatically included since 1986.
Here is the applicable policy provision:
7. Separation of insureds
Except with respect to the limits of insurance, and any rights or duties specifically assigned in this coverage part to the first named insured, this insurance applies:
A. As if each Named Insured is the only Named Insured; and
B. Separately to each Insured against whom a claim is made or suit is brought.
Of course, such a request to remove an exclusion that does not exist is ridiculous. The likely reason for most of these requests is because the attorney who drafted the contract is referring to some old boilerplate contractual provisions from decades ago.