If there was a sensor measuring the fluid (like the oil pan sensor) then there would likely be more than two wires, which are the wires that power the actuator. If the sensor measured the capacitance of the fluid, as the engine oil sensor does, then not resetting it would only result in an erroneous indication of the hours remaining until the fluid is out of spec. Not critical to operation, and the only effect would be the indication, not the operation of the actuator.

Or, if the reset is in the computer (not the actuator), then the reset could involve the actuator functioning, and the computer monitoring clutch engagement times, and deciding what the engagement point is given the current fluid properties. Then, it would use that reference point to apply the appropriate clutch pressure for the desired front/rear awd bias. In that case, not resetting it could result in incorrect application of the clutches in the transfer case. If it was a small difference, you wouldn't likely feel a difference or notice any wear difference. If it was a larger difference, you would prematurely wear the clutch plates in the transfer case (if it was too loose) or wear out the actuator by overstressing the plastic gear (if it was too tight). You wouldn't know about the result of not resetting it until you experienced such a failure, and even then it wouldn't be conclusive, so it could be attributed to an unlucky coincidence.

It would be like changing a camshaft and not adjusting the valves (on a vehicle where that is required) because of the assumption that "it was fine before, it will be fine in future". Or changing steering components and not getting an alignment, because of the assumption that nothing else changed. Faulty logic IMO. Still feeling lucky?

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue