About the alarm company example you made. If the user did everything right and the system still failed to triggers should the alarm company not be held responsible?
It's not that simple, unfortunately.
You're assuming the user did in fact do everything right (is the end user really going to admit he forgot to close a window, for example? Or never armed the alarm?) as well as the fact that the hardware performed flawlessly (even alarm systems have firmware / hardware bugs, cables get broken, batteries run flat, etc.).
So what typically happens when something goes wrong is that everyone start pointing fingers. And if the law is by default on the side of the consumer, it will get abused.
You might not believe it, but there are many consumers out there who will use any method not to pay or be held responsible.
Another real example (got stacks of them

): Small company completes job. Final invoice: R20K. End users says stuff you, won't pay, sue me. Legal costs more than R20K. Small company rather walks away from final payment (most of the profit on the specific deal). Customer knows this will happen and use system to his advantage. Small company could fight it (and probably win eventually) but need to get on with their lives and actually make money to pay salaries, suppliers, etc.
So I'm not saying consumer protection is wrong, far from it. But I am saying that it will get abused much more than what most people realise. And it could well create an environment that scares the SME away.