[RunSet]

Since an effective access control would by definition not be subject to circumvention, there is no conceivable situation where someone might be guilty of circumventing an effective access control.

https://www.merriam-webster.com/dictionary/effective

An ineffective access control? Perhaps, but the DMCA doesn't mention those.

[hunter2_]

Well, the thing YouTube does (whether you call it an access control or not) does actually have a measurable "effect" on people. It makes those people seek out third-party tools when they don't perceive any other reasonable way of downloading the work. So by that logic, it's pretty effective.

Nothing is ever 100% effective -- even the best encryption is technically a compromise -- other than OTP. YouTube just happens to be on the low end of effectiveness; the third-party tools likely wouldn't exist if it were on the high end. But I guess even slight effectiveness is enough for DMCA purposes.