If you had enough motivation, you could learn to decode the picture by squinting, and understand the audio by enough exposure. That came very handy to many a teenager on late Saturday evenings.
In the UK we had the Red Triangle: https://en.wikipedia.org/wiki/Red_triangle_(Channel_4) where we stayed up late for the hope of some sexy fun times, and we were exposed to culture and not nearly as much nudity as we had hoped for.
Where I lived the paytv encryption just removed the sync signals and audio and by finetuning the TV you could get a fairly clean black and white picture. It sounds similar to Discret 11 but it wasn't quite the same.
Only with a major scene change (eg day to night) this would need retuning. And this type of content didn't really do that, as most of these movies take place in the same bedroom :) so it was not a bad way to watch it.
Still supposedly, the hardest part was finding the strainer in the kitchen without waking everyone in the house.
And the saddest part was discovering that it didn't work.