The WK2 blind spot uses ultra wideband radar. Some RADAR detectors that detect POP guns will falsely alarm with Blind spot detectors, commercial alarm systems and radar detectors in other cars.
"There is a well known issue involving the some Side Assist feature, which senses cars to the side of your car and flashes a warning if you activate your turn signal at the same time as the system senses a car in your "blind spot".
Unfortunately there seems to be no way to turn the interfering signal off - although you can deactivate the Side Assist feature, the radar is still active. The solution is to deactivate the POP feature.
POP is a feature of certain radar guns manufactured by MPH Industries that is intended to defeat radar detectors. It emits radar in very short bursts - on the order of 67 miilisecods - to take an initial reading of your speed so quickly that the radar detector doesn't have time to recognize the presence of radar and signal an alert. Presumably the police officer can use POP on a series of cars without any radar detectors ever knowing that it's being used. Then if the initial reading using POP shows you are speeding, the officer switches his radar gun to standard mode to get a longer and more accurate reading of your car's speed. Of course now your detector will indeed react, but since he's already got you in his sights you are nabbed before you have time to slow down.
Radar detector manufacturers have responded by setting quicker reaction times to the initial burst of radar energy. Thus if POP is used on a car in front or behind yours, your detector will sense it and signal a warning - hopefully before the officer aims it at you. But this change has the adverse effect of causing more false alarms from noisy devices such as commercial alarm systems, radar detectors in other cars, and many Side Assist features."
I wonder if someone cleaver has managed to turn the collision avoidance and side radars into speed and traffic camera RADAR jammers... but officer its just a collision avoidance system
By the way, I don't think you can turn the WK2 side RADARs off, they seem to be always on regardless. Note that its not only the WK2 setting off K band detectors, Mercedes, Audi's, and BMW's are notorious. The WK2 adaptive cruise uses a higher frequency; radar detectors should not alarm.