Yes a good example of why reform from top down government to local authority is required.
Common sense is difficult to define but if there was a way of applying it consistently to different areas of law be it civil, criminal, human rights, planning and so on we would live in a much fairer society.
The problem of course is that one person's common sense is another person's extremism. As society has developed and become more sophisticated it explains why for example in criminal law there has been a tendency to move away from simple well established common law to ever tighter statutory acts of parliament. This is to supposedly counteract loop holes and technicalities whilst simultaneously negating any bias or agendas that the adjudicators may hold. .
What then becomes a problem in that the law becomes so specific that people can then exploit such precise definitions. It's not beyond the bounds of possibility that Cummins has cynically yet legally exploited tight legal definitions whereas the lady had neither the support or resources to cope with her circumstances.
So perhaps on balance we should seek to reign back from tight legislation and look to the simpler concept of common law style legislation which allows for a broader brush and those applying and interpreting the law to apply that common sense. That in conjunction with creating good old fashioned stated cases to cater for the quirks and unique cases that will arise as a result of broader based laws/rules. Theoretically if it were so you could have ended up with opposite polar outcomes to the examples presented here.
The significant caveat is you then need to invest very heavily in procuring judges etc. who are as near to beyond reproach and agenda free as can be humanly possible thereby ensuring genuine fairness and integrity in application of those laws. A very difficult task in it's own right I would suggest.
There are no easy fixes and that is why you will continue to see many cases of apparent injustice where people are left shaking their heads in disbelief at seemingly ridiculous harshness or leniency. It explains why many lawyers will tell you that laws are not actually about justice but are simply there to end the argument; the inference being to draw a line under the grievance regardless of the outcome.