Google considers any account NOT created by an organization (such as CU) a personal account, and Google does not share information about your personal accounts. Therefore, even though some campus members previously used @colorado.edu email addresses with Google, there was no way for CU to know whether your account existed, nor whether an account conflict would be created.
Additionally, Google’s system does not support automatic data migrations between personal and organizational accounts. With no way to target our communications to impacted users and no technical actions we could take to mitigate this impact, we were forced to support this issue only after you discovered your account conflict. We sincerely apologize for this inconvenience and intend to support our users to the best of our ability.