This topic was passing by when I was searching for "sort". I would like to revive it, since it almost immediately changed to a discussion about recovering from unwanted operations. The subject (i.e. the first paragraph of the OP) is still on my wish list because I want to prevent such situations. Sometimes I don't even notice that I made a change. I never feel quite comfortable in apps where I'm exposed to that danger.
Edit:
Oh, sorry, mistake, I saw it here, as item 4.
Edit 2:
It's thinkable to combine this with the checkbox for tasks, so that a checked task can only be modified after being unchecked again. However, many people will object to that idea, I expect. Better an autonomous lock control.