Oh gosh!!!
Why are you so afraid of the lawyers. They are the human's best friend!
If they could do something useful perhaps they would become humans!
Nearly every image format has a comment field. Most the applications write
their name in it. By default this is done by the application which made the last
change.
If you want humourous, anoying and pubescent comments then you should have a look into the animated Gifs. In the comment field.
So it is not a crime, Everybody does this. Adobe, Gimp, Corel, Microsoft. And a horde of young boys.
I don't like Adobe. In the early days of image processing they bought all these little companies to get the monopol. I learned to work with image with the help of the PhotoStyler. Version 2.0 appeared and after that Adobe had bought it and it disappeared. [ Today this is for free in some museum ].
Not a big issue. But one of the loose ends where we should care about Open Source.
Winni