What are the potential risks of hacking? It can be fairly stated that no-one ‘needs’ a connected fridge or even central heating controlled from a phone. Just set the timers or switch them on when you get in. Moreover, no-one ‘needs’ a SMART meter, particularly when it’s tied to a supplier.
There is no technical reason devices can’t be made safely, but attitudes and practices in the industry mean that safety is generally poor. Most security hacks are down to users’ sloppy practices.
As with any software-driven system, one major risk is the likelihood of having that system out of commission and the potential mitigation measures in such a scenario.