Your service running itself is a good idea for avoiding you doing a lot of work, but if you got hit by a bus it is likely someone would shut off your credit cards that pay for services your services depends on and even if it's a box in your house it will end up unplugged. I'd strongly advise some business continuity involving a very trusted friend or family member who can be your second in managing the service at minimum, who has access to everything and knows what to do already.
I hope you don't take my comments as too much of a knock, what you're building is hard and worthwhile, and I wish you success with it. I'm on FastMail but that doesn't mean I always will be, and I like to have good options by good people.
I also hope to solve any bus factor problems before leaving beta. Right now if I were struck down, I think I'd still have about 9 months worth of free AWS credits on the account running the service, plus any profits. (It's not quite a self sustaining business yet, but it's not that far from it either.)
Anyway, good luck getting away from gmail!
Keep up the good work!
https://news.purelymail.com/posts/blog/2019-06-21-deliverabi...
Unfortunately there aren't any easy answers. You'll have to be persistent.
I shelved my one main doubt (I don't think much of Roundcube) and started the process today. Seems like you've done a really good job. Recipients have been getting all my emails, and I have found the integrated migration tool invaluable in getting set up.
Good luck with the venture.
"could" or "would"? Is there something in place, and have they agreed to this?
As to the terms of service, as far as I know the clause you quoted is fairly standard cover-your-ass. I've probably seen it in a few other service terms. Presumably, Fastmail words it as they do because they've covered all the reasons they might want to do so in their terms already, and have decades of legal experience.