I’m looking at this policy currently, and I think it could use some adjustment.
I’ll start by saying that Canada should have this implemented to some degree, whether “voluntary” or “wide spread” is debatable. There is no legal requirement to carry ID in Canada, but virtually everyone has some form of government issued ID. For most people it’s their driver’s license, but I have met people who had an ID card that is not a driver’s license. Government services want to identify the person they are delivering service to as part of the record keeping. I don’t know what the procedure would be for someone who doesn’t have ID, I’m sure there is one, and I’m sure it’s a head ache. Government ID is also required to verify age when selling alcohol or tobacco (and probably cannabis now, I wouldn’t personally know), and saying “get an ID or no booze for you!” is a pretty effective method of getting most Canadians to get ID.
On to the details of the policy: It starts out with a pretty strong hit to liberal opinion, 18-20ish percent, and goes up to 60ish percent at maximum strength, called “heavily enforced”, on a flat line. This is something which should definitely have a curve to it. People aren’t going to get bent out of shape about an ID being available to streamline processes where identifying oneself just makes sense. Sure, there will be a few weirdos saying “that’s the government tracking you man!”, but most people don’t care. On the other end, “heavily enforced”, I can just imagine being out for a jog, and having cops stop me just to prove that I’m carrying ID…that wouldn’t end well. I know you don’t like to change too much at once, but I think bumping the negative liberal opinion modifier from maxed out ID cards from 60% to 75% wouldn’t have to much of a ripple effect. On the low end, maybe 5%, then make the line curve.
The lines for crime and violent crime should probably curve as well. Conservatives and patriots seem to be filling the roll of authoritarians in liking this policy. Their opinion impact is probably fine, the like the policy a lot just for existing, and like it somewhat more as it is increased.