I have no problems with them issuing a ticket as you say, how do they know you are telling the truth if you say you forgot to put the new one in your car, but for someone with a clean record it would be nice for a warning, logged somewhere so it is a one time thing, or like they did when I lived in the UK which is you have a window of time to go to the local police station and verify your documents. So if you get pulled over and reach for your wallet to show your licence, or insurance or whatever, and you realize you left it in your other pants, coat whatever. You have a period of time, can't recall how long say 48 hours, to turn up at the police station and present your valid document to avoid the fine/ticket etc. That way you are not punished for something as simple as forgetting a piece of paper which has no consequence to anyone (providing you are actually licenced, insuraed etc.)
Really I don't even have that much of an issue with paying the fine, it is all the talk of convictions staying on yoru record and affecting your insurance rate that is the thing that frustrates. It would be ironic to receive an insurance rate increase because you forgot to put your new insurance card in the car...
In my case it was more frustrating that it was a second ticket in addition to the disobey sign, which in its self was a simple error, turning the wrong way out of a parking lot, on a quiet residential street (i.e. not running a stop sign into a junction where you could cause a collision etc.). So for someone who has never even been pulled over or ticketed or even got a parking ticket in 15 years of driving it is frustrating to have a simple error like missing a turn restriction sign and forgetting yoru new insurance card in your car suddenly turn into nearly $200 infines, 2 demerit points, 2 (potential) convictions etc.
My issue isn't with the offences themselves, they are what they are and people make mistakes etc. it just seems that the punishment is a little out of balance to the offence. When you already try and follow the rules of the road, as opposed to intentionally breaking them i.e. speeding, running stop signs, talking on cell phones etc, and still you know that there are police cars hidden around junctions just waiting for you to make one tiny mistake, it kind of takes the enjoyment out of driving. Especially in the city where there are so many signs, lane restrictions, turn restrictions, time based rules etc. I find myself almost paranoid about missing a sign and makign the same kind of small error etc.