Steve,
I take your point, and like indicated in another part of this thread, for most parts of our stack its standard practices. It is only when managing certain external resources that we take a bit of extra care, and that is in a library that is not outwardly exposed.
I agree with you also that I don't even know if this is a thing that is possible in python unless the type checker could assume that a caller was meaning to move a variable when they called a function declared with move. And of course this would still be at the type checking level, and not at execution time.
For our use case, we put a move indicator at the point the function is called, and not in the signature of the function itself (because of what you indicated above), signaling the intention was to move it. It's not really much different than f(x); del x (though of course there are details). And so python does provide everything needed already to ensure one logical binding (and of course there are N other solutions people can think of, guards, exceptions, etc).
My point was more that if there was a way I could indicate to a type checker that it may be unsafe for anything to use a reference to this object after this function call it would be helpful(as I might have forgotten behavior of functions, or simply not been paying attention).