For instance, it is wrong to say
I am Japanese and I have never heard my parents or anyone use this. Maybe it's not "wrong", but no one ever says it in Japanese.
Is there a rule?
Anyone will never understand, what シャワーは／が 浴びてある or 歩いてある is all about.
Both of them are wrong anyway.
Both these verbs are grammatically intransitive not transitive. I checked the dictionary for confirmation.
The construction you're talking about is only used with transitive verbs, perhaps most commonly with the verb 書く.
「立入禁止」と書いてある。If you're Japanese you should be VERY familiar with this phrasing.
ドアは閉めてある。(The difference between this sentence and its intransitive counterpart,ドアは閉まっている, is that the former implies human involvement; the door is closed because someone closed it.