How would one practically verify and certify cybersecurity of a product? Even payment smartcards sometimes come with non-malicious maintenance backdoors. There seem to be little to no academic theoretical basis to this whole software security thing.
Given the challenges of techniques like TLS interception (i.e. through pinning and other good security features), about the only measure I can see left is network isolation.
You can set up a local network that has no WAN connectivity on it. About anything else is difficult to verify even the most basic of security properties. Certifying is another step up (although you could argue certifying is just a third party saying something passed a finite list of tests) - the real challenge is defining a meaningful certification scheme.
The trouble is that these set out principles, but it's hard to validate those principles without having about the same amount of knowledge as required to build an equivalent system in the first place.
If you at least know the system is not connected to a WAN, you can limit the assurance required (look for WiFi funcitonality, new SSIDs, and attempts to connect to open networks), but at a certain point you need to be able to trust the vendor (else they could put a hard-coded "time bomb" into the code for the solutions they develop).
I don't see much value in the academic/theoretical approaches to verification (for a consumer or stakeholder concerned by issues like these), as they tend to operate on an unrealistic set of assumptions (i.e. source code or similar levels of unrealistic access) - the reality is it could take a few days for a good embedded device hacker to even get binary firmware extracted from a device, and source code is likely a dream for products built to the lowest price overseas and imported.
We're not just talking about random consumer hardware : with security issues like these, I don't see why closed source software would not be just banned.
Are you suggesting using smart phones should count in "not allowing it in"? Then yes, I try to where possible. I do not depend on a smart phone. All functionality that are operationally necessary can be done elsewhere without major delays or impact.
I do not allow any system into my environments (at home and at work) that requires a third party data connection function.
There are way too many incidents where a provider, cloud or otherwise which required connection failed for various reasons.
(e.g., Cisco Spark Board, Xerox ConnectKey, Google Cloud Print, WeWork's Connected devices, Lattice Egnines, MS Groove Music Pass, Shyp, Adobe Business Catalyst, Samsara, Zune, FuelBand, Anki Vector Robot, Google Stadia, Pebble)
Despite this, I am very leery of regulating solar power specifically.