This is from an actual present-day huge-firm client engagement letter, of 2017 vintage (emphasis added):
The Firm and its affiliated entities represent clients in a broad range of industries and in a wide variety of legal matters. Absent an effective conflict of interest waiver, conflicts of interest could arise that could deprive you or other clients of the right to select the Firm as their counsel, and preclude us from representing you or other clients in ongoing or future matters.