@gergely I wasn't even supposing that any app should be allowed to take screenshots, ever. It should be a system-level thing that doesn't concern apps at all. If for some reason apps do need to be able to take screenshots, then yeah, there should be a permission.

@diodelass @gergely And that android app that forbids screenshots fails in my QA department. If my team can't screenshot an app's incorrect behavior, we can't test it.
<mike. drop.>

to elaborate further, this is how I think screenshots ought to work:
1. operate at the OS (or perhaps even hardware) level, independent of any app
2. be completely undetectable and unaffectable by any app, unless explicitly allowed by a permission setting
3. be activated exclusively by pressing the power-volume-down button combination, with no support for programmatic activation without explicitly setting a developer option

Sure, this might ostensibly make things like Snapchat harder, but that's really not a problem that can be solved by allowing apps to interact with the screenshot process in the first place.