I also found some amusing false positives (syntax errors that weren't valid print statements in Python 2):

    print [/
    print /
    print )    # but not "print)" !
    print]

None of these matter though.  Perhaps more concerning is how many things are valid syntax, despite making little sense:

    print [42]
    print

Still I like the idea -- even if it only catches 50% of all print statements that would still be a huge win. (And I think it's probably closer to 80%.)