A social custom would be established that buttons are only to be pressed by knocking foreheads together. Offering to press a button in a fashion that doesn't ensure mutuality is seen as a pathetic display of low status.
Hah. Status is relative, remember? Your setup just ensures that "dodging" at the last moment, getting your button pressed without pressing theirs, is seen as a glorious display of high status.
To whom it may concern:
This thread is for the discussion of Less Wrong topics that have not appeared in recent posts. If a discussion gets unwieldy, celebrate by turning it into a top-level post.
(After the critical success of part II, and the strong box office sales of part III in spite of mixed reviews, will part IV finally see the June Open Thread jump the shark?)