Good idea but only likely to work if the incoming light isn't very high intensity. It's possible though because cops tend to get older tech than what is available according to some envious comments from LEOs in training.But if a GG wanted to be sure, he could quickly flash on/off his own handheld flashlight (aimed not at the eyes but in the general direction of the light) to confirm it's indeed a uniformed officer approaching.
Overpowering a wall of high output light requires even higher output or even multiple higher output light sources. I once needed a handheld, weapon light, and headlamp along with taking an offline position just to make a shot on steel "holding" a last gen 1000 lumen surefire fury. That was near 3000 lumens on my end. However, now with my current higher candela tech it would probably be a bit easier to cut past through the barrier, assuming the opposing light source hadn't upgraded too. And forget about not aiming for the face. A wall of high output light shows no face or silhouette to aim for or away from.