Here, in the UK, there is currently a massive scheme to replace all old mechanical (both gas and electric) meters with smart meters. Installing your safety valve at the same time wouldn't be any more work and the electronics could be incorporated into the smart meter electronics. It may be worth your while to investigate that.
However, I don't understand how your valve could work. The pressure drop when my central heating boiler fires up is vastly more than a small, yet still dangerous, leak would cause.
Also, when the valve trips, who gets to reset it, the customer or the utility?
If reset by the customer, in some cases it would render it useless. (idiot customers*)
If reset by the utility, there would have to be a dedicated team for that to avoid a prolonged break in service and, therefore, extra expense for the utility.
*I've seen a whole fusebox where blown fuses have been replaced with kitchen foil, in a commercial kitchen, so don't tell me that there are no idiot customers.