Very nice, semantics are clear and use cases are compelling.
Can we defer discussion of how to roll this out for a little bit, and see if there is consensus that:
a) benefits of having this outweigh risks
b) we're all happy with exact semantics
Then we can have a knock-down drag-out argument about whether it should roll out as a soft fork, wait for a hard fork, be combined with some other things that it would be nice to add or change, etc.....