>I wouldn't even think twice about banning CSAM outputs.

Same, honestly. And you'll probably catch a whole lot of actual legitimate usage in that net, but it's worth it.

But you'll also miss some. You'll always miss some, even with the best guard rails. But 99% is better than 0%, I agree.

> ... and just expect the user to use it legally?

I don't think it's entirely the responsibility of the builder/supplier/service to ensure this, honestly. I don't think it can be. You can sell hammers, and you can't guarantee that the hammer won't be used to hurt people. You can put spray cans behind cages and require purchasers to be 18 years old, but you can't stop the adult from vandalism. The person has to be held responsible at a certain point.