&gt; See that&#x27;s the problem with anecdotal evidence.<p>I&#x27;m not the one who said &quot;not very likely&quot;. I&#x27;m not offering my story as evidence, just as an explanation for why I&#x27;d like evidence.<p>&gt; Do that in Rome, you&#x27;ll come back to find none.<p>I was speaking of the &quot;I am going riding now&quot; case. In Rome can you leave your bike outside overnight? In SF you can&#x27;t, so people store bikes and helmets indoors. In which case, I&#x27;d submit that storing them together is a pretty good idea.<p>Helmet theft might be a problem here in the &quot;I am already out riding&quot; case. Where I worry about that here, I clip my bike to my bag, so again it&#x27;s not a &quot;I forgot my helmet&quot; problem.