I remember reports from over 20 year ago about LA gangs allegedly painting guns in this manner to try to fool cops. It's nothing new. Mass media was alleging the same problems back then.
Since this idea has been around for decades, you'd think it would have caught on by now and be a huge widespread problem. I personally have never seen anybody ever using a real gun painted like a toy. Also, when mass media displays "arsenals" after busting criminals, how many brightly painted guns have you seen? I have personally seen zero.
I don't see how a pink AK-47 would give a policeman pause. The circumstances would determine the seriousness of an encounter. However, I admit I could be wrong because I have no personal experience with being confronted with a pink AK-47.
My girlfriend wants a pink Glock. If that gets her to shoot, so be it. Who says a gun has to be black? The women in my life who want to shoot do not get excited, like I do, about nice wood and blued steel.