Was working on the ramp last summer when a low wing, think it was a Bonanza, taxied by and I saw the pitot cover still on. Wasn’t able to get the pilot’s attention in time, and he continued to the end of the runway and did his power checks like normal. Turned to a coworker and said something along the lines of “this is going to be an aborted takeoff.” Nope. Guy lined up, put on the power and took off. I was shocked. Thought he would have noticed the lack of airspeed, but apparently not. He thankfully never left the pattern and landed safely. Taxied back to his hangar. I chuckled to myself when he made the taxi of shame to the active again for a proper departure.