Ask HN: Any methods to detect Safari content blockers, yet?

I'm just curious and I'd like to experiment with the detection of content blocking in iOS 9. The aim would be showing something like a very small popup like The Guardian does, with a sentence like this: "Looks like you're blocking ads. We're cool with it, but here's how you can support us in other ways". Has anybody found a way yet? With desktop adblocker that block any js with the word "ads" in the filename it's much easier...