When a politician of the political party in power talks to a member of the former Government political party, he/she may say 「お宅の党の政策のつけが今こちらに周ってきているんですよ。」. It is less polite than saying 「～さんの党の政策のつけが・・・」. It sounds equal to say 「あなたの党の・・・」 here but 「お宅」 implies that the relationship between the talking person and the second person is not close and rather estranged compared to 「あなた」.
Another situation would be when a neighbor who you do not know very well asks you, 「お宅の庭の木の実が周辺に散らばっているので片付けてもらえませんか?」. It's less friendly to be told than 「～さん、木の実が周辺に散らばってるので・・・」. So it implies that the talking person does not necessarily wants to talk to you unless he/she wants to solve the issue. Here also 「あなた」 could be used like 「あなたの庭の木・・」 but the differences are subtle and I think 「あなた」 can give a sense of acknowledging the person while 「お宅」 does not. So I would say in general 「お宅」 (used as the second person) implies unfamiliarity towards the second person.
If a customer is called 「お宅」, it sounds really rude. For example, a waiter at a restaurant asks the customer an order then says 「お宅、ご注文はお決まりでしょうか？」. It should be 「お客様、ご注文は・・・」. But if an illegal drug dealer says 「お宅、何にするか決まった？」, it sounds appropriate.
