The relevant Section 15 d (bolding mine):

Suspension of Use; Cancellation; Closure.

We, in our sole discretion, may limit your use of, suspend or terminate your privileges with respect to your Account (including your Reserve), Sub-Account, Card and/or Sub-Account Card with or without cause or notice, other than any notice required by Applicable Law, including in the event we believe there has been a breach in security or there has been unauthorized activity involving your Account or you have engaged in activity that is fraudulent or inappropriate (e.g., manufacture activity that is inconsistent with the intended use of the Account) or violates the terms of this User Agreement.