US law enforcement here. I'm kinda in the minority boat of my profession. I applaud Apple's stance on privacy as a consumer, and I believe in a person's right to privacy. I also must obviously get into devices as a part of my job. Generally speaking, when I need access to a phone, I'm usually not feeling guilty about it. I'm not going to write a search warrant for a phone unless it's a felony, and usually a bad one. Android devices are a joke. Apple can be tough, but if time is not of the essence, any phone can be broken.
That being said, we do a lot of our work with various federal agencies which I will not name, nor will I go into detail about. Suffice to say, if we want to get into the phone, we generally will. As mentioned about, a warrant will give us the ability to compel (by force if needed) access to biometric means such as a fingerprint or facial recognition. We cannot force you to give up your passcode. I won't go into the methods or tools available but they are out there. It would be in the best interest of any Apple product owner to be familiar with ways to disable the biometric access features of your device.
EDIT: The Constitution of the United States is held as a sacred thing. We are not accessing people's devices without probable cause supporting a warrant issued by a judge. It's easy to get a warrant with probable cause. It's almost impossible to get a warrant based on weak probable cause. Don't believe what movies and TV tell you-there is a rigorous set of rules in place for this kind of thing and the defense is entitled to all information we have, especially if it exonerates someone. If I get a warrant for your device, you can bet that I followed the rules and you are probably in trouble.
