Having occasionally forgotten, and had to do whitespace commits, I agree.  For Python code, there is never an absolute need for trailing whitespace.  Trailing whitespace in string literals can be done by parse time concatenation.
'''\
line 1
line 2
''' 'line with trailig space    '
Indeed, the trick is needed to mark the trailing space in the code.

I have thought about removing trailing spaces after each return, but pasting may be a problem.