Honestly, I've been doing that thing everyone suggests - where you research as many different versions of one effect as possible to come up with a combination of techniques that is ideal for you - and even just looking at two or three common effects ( ring & string, professors nightmare, anything with rubber bands) it's evident that everyone is reusing everyone elses material, sometimes credited, sometimes not, sometimes the person they credit credits someone else, who says they have no idea who did it first.
The people writing the books and making the DVDs seem to be okay with reuse of material, the community thrives on the organic imrpvoement and repackaging of old material. Other than a few notable examples of people stepping on eachothers original effects within a very short time (and either undercutting or overpublicising to choke the market), there's very little animosity amongst the authors regarding idea development.
The people who REALLY appear to get their hackles up over this are the readers. From their perspective it seems to be a case of "OMG! I paid £20 for this book and only half of it is new material, what a ripoff!" or "This is just based on a principle from Banachek, there's nothing new here!"
If the authors want to litigate, they will. If they want to publicise their distaste, they will (they certainly have a much greater reach than a forum post). The last thing they need is their respective fans getting into turf wars over a trifle ( or a triumph

), smearing eachothers names, and fracturing what is actually a very friendly community overall.
-Stacy