No, not hotlinking. I don't think hotlinking inherently could break a law, I think that would require some understanding that the host provides the content for one particular use and any other use would be a violation. There probably are sites with license agreements/terms of service that state as much in which case hotlinking would be breaking the contract. If ad blocking were illegal, it would be for the same reason.

Hotlinking could be involved in criminal or civil actions, e.g. used to perpetrate fraud or used maliciously (intended to use up host's resources or even DDOS).