A guy is building an app called #Monero Watchman that will send the user a notification in case of chain reorgs so that you can add hashrate.

https://github.com/NathanRizza/monero-watchman

It came about because of me posting this bounty after talking with Arctic Mine on Monerotopia

https://bounties.monero.social/posts/203/0-429m-a-monero-attack-alert-app