You might have been able to deflect more of this if you had made up a new type of security that broke the rules (something nobody could have expected), however I thought your example illustrated the issue very well. For me it is especially common to run into the field that could never be null but now is scenario.

I liked your article a lot, very nice write up. I tend to lean towards the idea that there may not be much of a solution for this. But it's better to look for one than to just give up!