Licensing: Embeddable widgets and noncommercial vs commercial use

Question

A theoretical question regarding licensing and embeddable apps aka widgets/gadgets many sites offer nowadays. I'm using Creative Commons licensing in my example as that would be the case if this hypothetical situation would be turned into a real one by me :)

Let's say we have a noncommercial site, www.noncommercialsite.org, that contains stuff made by it's users and licensed with noncommercial license, like CC-by-nc-sa for example, and they offer a widget displaying this stuff that can be embedded freely on any other site.

Ok, then let's assume we have another site, www.pay-to-use.com, that is highly commercial and can only be viewed with a paid user account.

So, the question:

If www.pay-to-use.com would embed the widget provided by www.noncommercialsite.org on their site, thus 'using' material licensed only for noncommercial use on a commercial site, would it violate the license?

And if it would, whose fault would it actually be? The site embedding the widget or the site providing one?

Answer 1

www.noncommercialsite.org offers a widget that can be embedded on any other site that abides by the license restrictions

www.pay-to-use.com uses that widget and doesn't abide by the license terms?

I'm no lawyer, but it would seem that www.pay-to-use.com is at fault. I don't see how www.noncommercialsite.org could be at fault here. Or am I missing something?

Edit, It doesn't matter which license this is. It could be an open source one, a closed source license. The end user is obliged to abide by the terms of whatever license that applies to the software they're using.