One broker that assisted was Oanda. They didn't guarantee that the stop per se, but they didn't even forgive any negative balance UP TO your stop. No broker will ensure any stop precisely because of these types of events. No on can forecast the future and that is why we must be careful.
Step you can take:Use a broker such as Oanda Trade with lower leverage - don't use ALL your leverage Keep just enough money in your trading account to correctly margin your account, for the leverage you may utilize. Take all other funds dedied to trading and place them in a safe interest bearing account. That way if you are wiped out with a black swan even you will just lose your margin and not your entire stock. Welcome to the real world of trading