Remember also that WAI is in fact a de-icer. To use it as an anti-icer can be very dodgy. As Denti says ice accumulation on wings LED's in ice crystal regimes is highly unlikely, and if it happens should be very minor. Once cracked off the LED should stay clean. Leaving WAI as a anti-icer, once the LED is clean, is a)unnecessary, & b) could cause flow back problems. Unlikely, but could.