Google Charts also allows you to set a legend. It really should be part of the graph.
E.g. this is the graph at this moment: http://chart.apis.google.com/chart?cht=ls&chco=ff7700,00...
I thought the reason for disallowing both a URL and text in a submission was to avoid this. Though, if a submission that requires a comment is acceptable, why not allow submitting both a URL and text?
I think a non-vote-able comment at the top wouldn't do as much damage as you might think. Maybe, instead, make it a rule where half & halfs get filtered/blocked.
Is this really that big of a problem? Really?