Opt-out is bullshit, it's unethical. Unless people specifically give their consent to their content being used for training data, and are compensated if they wish to be compensated for that privilege, then it's just not morally defensible. Legally defensible? Sure, maybe so. But we don't like to support companies who are merely abiding by the letter of the law, we want them to abide by the spirit of the law and of treating their customers with respect and consideration. This is not that at all. 😕