How do they stop the coming bank runs?

By closing the physical branches

(internet access can then be turned off with one button press at central office whenever things get hot)

https://www.news.com.au/finance/business/banking/bankwest-is-set-to-shut-down-all-60-branches-in-wa-as-the-company-goes-digital/news-story/e6df67eeef37a5f83a826b3ecb8d1610