I agree with your friend. Here's why:
OIL FILTER BYPASS VALVE
If you wait too long to change the oil and oil filter, there is a danger that the oil filter might become plugged. To prevent a plugged oil filter from starving the engine for lubrication, oil filters have a built-in safety device called a "bypass valve." When the differential pressure across the oil filter element exceeds a predetermined value (which varies depending on the engine application), the bypass valve opens so oil can continue to flow to the engine. But when the bypass valve is open, no filtration occurs.
The bypass valve also opens when a cold engine is first started. Cold oil can be fairly thick and may not pass through the filter element very easily. So the bypass valve opens and allows the oil to go around the filter until the oil warms up and flows more easily. During this time, any contaminants that are in the crankcase may be sucked up through the oil pump and bypass the filter, causing increased engine wear and possibly engine damage. Once the oil gets warm and the bypass valve closes, oil flows through the filter and normal filtration resumes.
