So I'm a grad student living in an apartment complex designed for college students. (Off campus living, not dorms.) Therefore, my apartment complex had a large 24/7 computer lab on the grounds that is free to residents. The computers are always on and logged in, requiring no account logins, 100% public.
What would prevent me from going to this lab when it's empty in the early morning hours, downloading a mining program on each of them, and leaving it running in the background of each? I would then have 18 desktops mining simultaneously for likely days on end at a time.
Would this be legal? Illegal? Gray area?
Keep in mind my lease includes "full 24/7 access to the property gym, lounge, and computer lab." Wink wink.
I'm pretty sure there is some legal fine print somewhere that would say you aren't allowed to interrupt or interfere with services provided.
Aside from that the simple answer is any network or systems admin would likely already be blocking that kind of traffic or application on their systems/network so the miner may not work at all. If they don't block it, they may have it set to alert to the activity and once alerted you could get setup to be caught by authorities.
Depending on how it's argued from a legal standpoint you could be accused of "hacking" or something else. It also could make you liable if a network vulnerability was created by what you did that lead to the network being compromised in some other way.