I work in software industry. Since the day one I was brainwashed with the term "ethics". You know why? Read on:
1. A candidate is looking for a change. Even after his final interview round and a great "We like you" statement the company is "working" on the final offer letter. A week and then 10 days go past, they are still working on it.
Excuses: "VP's permission is required. The HR team is out on a team building exercise. blah blah". Real reason: They are just buying time to find "better" candidates.
During this period the candidate can't choose a company from one of the offers: eternally optimist. Moreover, the companies always give this impression that offer selection is "unethical".
Now the candidate looses patience and asks for a final date. The company counters: "Do you have other offers in hand?". Now if you say Yes then they will declare you "unethical" and if you say No they will smile and make you wait for some more golden period.
Now if somehow you have a stronger arm and you want them to wait then you get feedbacks like "not upfront". You are supposed to get back to them in 4 hours! ha ha ha.