Does stun from artillery disable crew perks?

It doesn't affect perks according to the Update 9.18 bulletin:

... tanks in the arty burst radius ... have their characteristics temporarily weakened.

This leads to the question, "How you can get hit by artillery without a 6th Sense alert?" Possibilities include:

1. Counter-battery fire - When in bird's-eye-view artillery can see your tracers anywhere on the map and blind-fire at the source. See this video for an example. A teammate on arty's side, maybe somebody you're firing on, could guess your location and point to a map square for arty to watch.
2. Breaking things like trees/fences/poles/buildings/etc. or moving destroyed tanks because these are visible in bird's eye view.
3. If you were spotted earlier and didn't become unspotted 6th Sense doesn't alert you that you're still spotted. (Obvious but worth mentioning.)