If you get hit by a bus, who alerts your users and how? If your users aren't alerted, they may not realise that anything is amiss until AWS freeze your account for non-payment (for example).
I can't say that I spend a lot of time keeping up-to-date on the project leaders' obituaries for services I use. I don't imagine I'm unusual in this regard :)
Edit: This is just a rhetorical question, not a demand for explanation :) - just saying that being hit by a bus does not automatically mean that users are shifting off your service in 24 hours.
(God, that's a strange sentence to write. Sorry about that, Colin.)