Sure, I agree and I agree there is a copyright notice. Again, there is nothing said in a license agreement that states, "modification or alteration of this item is illegal". Absolutely nothing. Simply put, it is not said because it is not illegal.
As for a violation, in order for that to occur, something has to happen to deprive the copyright owner of profits. If I buy a DVD, modify it, and then resell it, how is that depriving the copyright owner of profit? IF they planed in the future to create this type of derivative work, then yes I might be taking profits away. If they have no plans to do so, then it is none of their business. They can sue for damages and get exactly what they lost, nothing.
A free public showing of an altered, copyrighted work does infringe on the copyright without a profit. Personal use is not an infringement, IOW, you can view the altered copy all day in your home. You can show your friends at the office. But you can't play it on the big screen at the local play ground for the public to see.
Fine lines, yes, but profit is not the only infringement. Misrepresentation laws do kick in at a certain point.