The cops from some countries cannot be trusted. > VPN companies operate at an international level. But that's subjective and I understand others may not feel the same way. Personally, I trust the US justice system enough that I wouldn't have a problem with complying with a valid warrant (after legal due diligence, of course). Like I said in another comment, you have to think about the odds of dealing with an LE request you consider unethical, and balance the consequences of providing logs or not providing logs. I think operating a VPN service for Chinese citizens to evade censorship and not doing logging to protect those users would be ethical, for example. I agree that it depends on who the law enforcement is. Do not leave such determinations to engineers and support staff. Let them first verify who and what authority is making the request.
I tell my client's to not even respond to communications from any sort of law enforcement or intelligence agency. And often times the person claiming to be a cop is either well outside their authority, or just lying about being a cop. VPN companies operate at an international level. What about a Chinese officer going after someone for "treason"? What about a Russian cop looking for someone who tweeted pics taken at a protest rally? Or what about a Canadian cop asking questions about a teenager in Sweden, someone well outside Canadian jurisdiction? Or what about the FBI agent asking for some celeb's home address? Rather than pick sides, the best answer is to just not collect the data in the first place.
An FBI agent going after someone distributing child pornography is a rather sympathetic police action. I guess that depends on which law enforcement you are talking about. I also think that explicitly not keeping logs to protect users from law enforcement is shady to say the least.