Artificial Intelligence (AI) assistants have been a hot topic for a few years. Popular solutions - such as Google Assistant, Microsoft's Cortana, Apple's Siri, and Amazon Alexa - are becoming resourceful AI-assistants for general users. Apart from some mishaps, those assistants have a successful history in supporting people's everyday tasks. The same cannot be said in industry-specific scenarios, in which AI-assistants are still a bet. Companies combining AI with human expertise and experience can be stand out in their industry. This is particularly important for industries that rely their strategic decision-making processes on knowledge workers actions. More than another system, AI-assistants are new players in the human-computer interaction. But how and when should an AI-assistant interfere in a knowledge worker task? In this paper, we present findings from a case study using the Wizard of Oz approach in an oil and gas company. Our findings begin to answer that question for what kind of interference knowledge workers in that domain would accept from an AI-assistant.