In the EU, this isn't a problem. You're free to reverse engineer the structure of APIs/protocols/data formats to integrate third party apps with it.
Morally, I don't think there's a problem either. Heck, you could build something cool on top of it. That's what I would do.
I don't even see reverse engineering APIs as a vulnerability. A ton of APIs (i.e. used in mobile apps) can easily be reverse engineered.
In the EU, this isn't a problem. You're free to reverse engineer the structure of APIs/protocols/data formats to integrate third party apps with it.
Morally, I don't think there's a problem either. Heck, you could build something cool on top of it. That's what I would do.
I don't even see reverse engineering APIs as a vulnerability. A ton of APIs (i.e. used in mobile apps) can easily be reverse engineered.