its not as easy as it looks like.
The poker site has the right to ban you and keep the money in the account, if you contravene their terms and conditions. (referring to Bot T&C only which are not illigeal like other T&C are
)
You don't break any laws, as long as your bot is playing a standard ai/rule based system, using naything other players have access too.
If your bot tries to sniff e.g. network traffic and tries to get any hidden informations like holecards etc. thats breaking the law. If you have more bots teamed up at the table, its a law breaking collusion
Probably the part which hits most of you. You also break the law if you are using fake accounts.