If someone doesn't lock their front door and you enter their building, you're still trespassing. Especially if it's your competitor's front door and you're repeatedly entering the building to scout the place out for financial gain.
"You wouldn't open an unlocked door" is the "you wouldn't download a car" of infosec. The later redefined theft as not requiring anybody to be deprived of a good while the former has the same flaw, you arent deprived of any good, you aren't harmed, you haven't been coerced or forced - i.e. It meets none of the common law definitions of trespass[0]
[0] but it does explain why ddos attacks, spam and stealing user data are trespass because they do meet those definitions
There's a difference between "opening an unlocked door" and opening it, walking through it, making notes of everything behind it and repeating this room for all the other unlocked doors and then doing that pretty much continuously for days, weeks, months or however long Uber did it.
I would totally open an unmarked unlocked door in a public space that has locked doors clearly marked "restricted access", especially if the layout of the place I'm visiting suggests that there would be something interesting there.
That's pretty much what it boils down to, no? Just because you didn't document an endpoint doesn't necessarily mean it's restricted access. In fact, if the end point is accessible, and you have other sections of your service that require authentication, then it's very much the exception that proves the rule — the fact that you specifically forbid access to some routes reasonably means that, in general, I'm allowed access to unauthenticated endpoints.
> collected and analyzed the data Lyft provides
they did it without permission