Hmm, I guess I also left out my feeling that "probably illegal" in this context more suggests 'Well, crap, neither of
our companies could dare rely on it without fear of being sued into oblivion' than any sort of direct accusation.
Sort of the way some still fear or denigrate Linux just in case there's some unauditable/unprovable bomb of a commit lurking back in its history. (...though even then, removing the bomb should make it clean, though Linus and distributors might have some cointoss risk of liability, strongly dependent on knowledge and intent...)
Evert's not a native speaker, right? That's a bit of a mess of a concept to express succinctly, especially when the object is a project you're 'competing' with.
