As a percentage decision, bunting has a lesser success rate by non-pitchers than not bunting.
Wasting an out lessens the chance of scoring even one run.
Man of first no outs: chance of scoring at all is .499.
Man on second with one out: chance of scoring at all .477.
Even if the bunt attempt was 100% successful, the odds get worse.
The average runs scored?
Man on 1st and no outs: 0.84
Man on 2nd and one out: 0.65
With man on first and second with no outs, the bunt looks like it might be a tiny bit better for scoring just one run, so I guess one should never say never.
1st and 2nd, no outs:
.649 with no bunt to .695 after successful bunt (2nd and third with one out)