Exactly. If I just nilly willy connect to your server, try a password and it works and I immediately disconnect, will that get me in trouble in the UK? That would be worrying.
The Theft Act 1968 defines theft as dishonest appropriation of “property belonging to another with the intention of permanently depriving the other of it” (and then waxes lyrical about what, exactly, that means: https://www.legislation.gov.uk/ukpga/1968/60/crossheading/de...). Just going by that law, I would say "it depends".
2. But if you make a stab at shoplifting and you are successful and give back the item, did you break the law?
I am not a lawyer I am just asking.