...I don't know whether or not Delta likes musicians. Clearly they don't like people who rip them off.

It's all very well being self-righteous and legalistic, but the action Delta took could well backfire on them if the story gets widespread publicity as it's clear from the response here that many people feel their action was unreasonable and probably unfair.

There is the case of the airline who would not reimburse a musician for damage to his guitar. He wrote a song about it and put it on You Tube. The result was a dip in the number of people travelling on the airline in question, so whatever the rights and wrongs of the case and I don't think anyone is denying that Delta were entitled to take some action. It's just that the action they took seems disproportionate and I think all companies need to think carefully about what is a reasonable penalty in such cases.

Whether or not the rules are reasonable is another but not unrelated issue.