As mentioned in the Addressing strangers without knowing the name thread, 敬語{けいご} often communicates the implied actors in a sentence. The thread titled using 美化語 in 謙譲語 verb forms does not make sense, right? raises the issue of whether 美化語 is 敬語, or not. Then, I noticed example sentences in the thread titled 「を」 object marker in this 受身形 sentence that would seem to add more clarity regarding whether 美化語 is 敬語 (and thus can be used to create implied actors):
Can an implied subject be created by adding 美化語 to 財布:
usage case #1
"泥棒{どろぼう}に財布{さいふ}が盗{ぬす}まれた。"
"泥棒に お 財布が盗まれた。"
Here, both are ok. The "お" is optional because the owner of the wallet is not known. Personally, I would not add the "お".
usage case #2
"泥棒に財布を盗まれた。"
The use of "を" implies that I am the owner of the wallet. So, that means that I cannot make the wallet honorific. which means that, if 美化語 is 敬語, then I cannot say:
"泥棒に お 財布を盗まれた。"
In essence, this the progression:
(1) "泥棒に財布を盗まれた。" // ok. The implied owner of the wallet is me.
(2) "泥棒に お 財布を盗まれた。" // whoops. I have made something that is mine, the wallet, honorific by adding 美化語 on the wallet.
conclusion
In usage case #2 (modify 財布 with を)、 adding 美化語 to 財布 is still grammatically correct, but sounds unnatural because I am misusing honorifics?