It appears the html code that Bing picks up is:
<div id="bb-miinfohalf" itemscope itemtype="http://data-vocabulary.org/Product" class="lmt">
<h1 id="bbnme" itemprop="name" ... {stuff deleted by poster}
<span class="bb-saleprice">$<span itemprop="price">113.17</span></span>
<span class="hidden" itemprop="availability" content="in stock">in stock</span><meta itemprop="priceCurrency" content="USD">
</div>
What controls the generation of this code? (I made the html text red)
There are some items we sell that are drop shipped, and this saying it is in stock is misleading. This is why we do not have stock tracking disabled.