If we decide we're going to ship to CA, I'll add the prop 65 warning to my label. Not going to mess with trying to quantify acrylamide or any of the other thousand contaminants in a statistically valid way. CA consumers are used to seeing the warning literally everywhere from pumping gas to starbucks so in general it doesn't seem affect purchase intent unless you're specifically going after a "whole foods" market.
In general it comes down to your compeition. If you have a product that can be produced without the warning, you have an incentive to try and get rid of it. However, if all products carry the warning (such as insecticides, gasoline, etc.) then consumers will likely tune out the warning.
As much as I want to bash on CA food safety, it's worth noting that despite the negative consequences on risk perception and company liability vs. public health, Prop 65 has encouraged a number of successes in pushing for innovation and elimination of certain formulations containing heavy metals etc. in various industries that benefit the public in general. While not my tool of choice, prop 65 has been successful at overall reducing the amounts of these substances consumers are exposed to, whether they were significant or not.
Some resources on consumer perception:
https://hbr.org/2016...s-arent-working
https://research.hks...=11338&type=WPN
https://digitalcommo...90&context=pubs