Haha! I remember this site was knocked offline back in 2004 and many other businesses were affected as well because a garbage truck cut through a fiber optic cable used by our ISP. https://www.elitetrader.com/et/threads/et-brought-down-by-garbage-truck.28810/
Earlier this year, the entire east coast on Verizon lost internet when someone in Brooklyn accidentally cut through a cable... https://www.businessinsider.com/verizon-fios-outage-cut-fiber-cable-brooklyn-2021-1 At least losing internet connection is a risk that can be minimized.
If the net is out... at a minimum one can use his cell to call his broker and do something defensive if need be.
Best to login using the phone - it's doubtful you would get through to customer service in the timely manner.
Traders with a lot of cash on the line trading shorter time frames should be using a multi-Wan router which allows you to use multiple ISP's at the same time, including cell like 4G LTE. This gives you load balancing so that are using all available BW. You can also setup custom link routing based on speed or packet error rates. This gives you a bullet proof network at a low cost - pretty darn close to it since any ISP problems are made completely transparent. You can get these multi-WAN routers for as low as $59, they work great and have other features like supporting VPNs, good firewalls, & plenty of statistics