This document bears all the hall marks of lobbying by the DNOs so they do not have to improve the local distribution networks to cope with a changing market and a redesign with new diversity factors. I cannot imagine the domestic electricity suppliers want to lose out on the opportunities to sell more electricity at times when it can be expensive.If it works anything like as reliably as the rest of the smart metering system, there should be no concerns any time soon. The first question is who owns the switch? Physically it is the property of the meter operator but it’s controlling a product sold under a contract with an electricity supplier and the most likely user of the switch in the case described is the DNO.
The next problem is reconnecting the supply. In the event of a power cut, the DNO could legitimately claim that it was beyond their control but if you deliberately disconnect a customer and they sustain damage or injury when you reconnect then you cannot claim that defence.
Personally I think that remote disconnection of individual domestic customers is a lot of trouble for a once in ten year event, especially as the required security seems to be behind a lot of the issues that have dogged the roll out. As was demonstrated in the August ‘19 event, applying DSR to large customers can restore frequency. What would have made the event less noteworthy is a bit of decent reliability engineering by a certain German train manufacturer.
It is the issue of who pays for local distribution network upgrades for domestic consumers being kicked down the road yet again. The changes needed for mass adoption of EVs are not huge in comparison with the new load that would come with a switch from gas to heat pumps for domestic heating compounded as it would be by a very high peak demand in cold weather juts when the heat pumps have their worst Coefficient of Performance.
On another note has anybody spotted the perfect places for large scale battery grid storage farms for balancing and stability are the brownfield sites in the Midlands of former coal fired power stations that already have grid power lines feeds on site. Reuse what we already have.