Case sensitivity in URLs

matched words not showing in bold when using upper case letters

[surfgatinho]

I just noteced that the URL displayed in green in the SERPs is not showing up matched text when the case is different. E.g.
search for blue widgets:
.../blue-widgets.html
BUT:
.../blue-Widgets.html

This is a)strange and b)slightly worrying.

Is it possible that this actually effects the SERPs - it might explain why there are a few spammy sites doing better than me