I'm curious as to the community opinion on the subject, as I am personally quite annoyed with the mechanic.
If you aren't sure, here is my personal definition of crouchspamming: Crouching and standing up rapidly behind some sort of cover, typically while using a sniper rifle, to attempt to abuse hitbox lag or to render yourself nearly impossible to hit otherwise.
This is a bit of a headache mechanic. As it stands crouchspamming might be seen as a "skill" like jumpshotting. Though this "skill" is technically the abuse of a bug or an unintended mechanic and often provides users of this mechanic with an unfair advantage over those who do not use/abuse it. Adding onto the annoyances of this "tactic" is that APB has no cooldown on crouching nor is your bloom affected by crouching, so a precision weapon like sniper rifles and rifles will find themselves extremely powerful using this mechanic. In addition, there is virtually no indication that the person using this "tactic" is about to stand up or crouch, so unless you are extremely skilled in instant pattern recognition and can sync your shots to the person crouching up and down (Which, while possible, is probably not easy) you will find the person in question essentially impossible to hit even if you were both using the same type of weapon.
So, what should we do? I'd personally propose making crouching/uncrouching cause your aim to bloom for a moment so that, while possible to pop out and shoot, you need to commit to standing for a moment to actually shoot with full accuracy. I wouldn't have it be very long, just for a second or two. That's more than enough for anyone engaged in a serious sniper duel to be able to retaliate.
I'd also be interested in hearing community solutions to this problem, or "problem" depending on your opinion.