It is a neat feature that there is a whitelist for certain key actions while the KDE Plasma lock screen is active. These whitelisted actions include volume and brightness control, and also media key actions. Here's a bit of the story behind it.
And here is a question about how to turn off the media control switches visible at the lock screen.
However, turning off the controls at the lock screen does not prevent the actions of media control keys (play/pause, switch track) to go through to any open applications playing media. This seems like a privacy concern to me.
Is there a way to deactivate media key actions when the lock screen is active? Or can the deactivation of graphical control switches be coupled to a deactivation of media key actions?