yeah, good point and nice suggestion.
I was trying to use theme settings to determine when some excerpts should appear over an image which is normally only shown on hover
In my case, options would be:
- always on
- only on touch devices (because hover is not really available on tablets/phones)
- only on hover (normal case)
Over recognising touch devices might not be a disaster in this instance 
I was just hoping there was some direct Site attribute I’d missed, but I’ll look into your suggestion. A mini CSS refactor with some concatClasses looks likely though …