[EM] Craig's strategy puzzle

[LAYTON Craig]

Bart wrote (in part):

>But as a practical matter, this isn't really necessary in order to know
>how to vote.  It's clear that approving C provides a several-fold
>increase in the likelihood of defeating D, more than making up for the
>utility compromise.

It's interesting to note that most of the people who responded to the
example thought that bullet voting A would be the best option.

>Whether to also approve B, or to just "skip vote"
>for A and C, is probably worth a coin-toss.

Is there ever a clear motivation to "skip vote"?  I had always understood
that there is never any incentive to vote insincerely in Approval.