The verb suffix '시' is normally used to give respect to the subject of the verb; yet it is easy to see examples where the verb subject is inanimate and an honorific isn't required:
다른 것이 필요하시면 알려주십시오 (from Darakwon via Naver Dictionary).
This seems like a hypercorrect attempt to use an honorific to be polite, when it is not correct; according to this Naver Knowledge Search answer, 필요하면 should be used in cases like this.
However, that answer is clearly about 'official grammar'; as I understand, officially, 필요하면 should be used, but in reality, many people use 필요하시면. What I'd like to know is the reality of the usage: what should be used in practice?
More concretely, if 필요하시면 is used, to an educated ear, does it usually sound like an unnatural hypercorrection? Or if 필요하면 is used, could it sound impolite/too casual? Or will both be accepted freely?