Python's stance is that the humans and the tools should use the same block identifiers. Sure there are other ways to solve the problem (like make the tools look for likely errors and warn the user), but Python chose the route of just getting people and tools on the same page - it's not a bad solution.
Sorry but it is a bad solution. I used to be a fan of indentation until I started writing large programs. Such big projects often require refactoring of the initial design and thus massive cut-and-pasting, with all the standard ensuing pitfalls.
This is a problem that clearly didn't occur to the Python designer and to this date is both unsolved and a major source of bugs.