I suppose that if somebody not only followed the exact sequencing of a previous course but also pretty much pasted its contents page into theirs (i.e. had the exact same headings, wording etc), there might be a case to be made; this would seem to assume, however, that there were something magical to the sequencing that would be easy for other
teachers to replicate (bear in mind that there is a patter and staging to any course beyond the text) - I know that I for one sometimes (often?) do not see what some teachers find so amazing about their own or other's materials, nor I suspect do people always appreciate the choices that I've made for my classes; basically, I feel that each teacher ultimately could do with writing their very own textbook(s), with translating whatever hard-won linguistic knowledge they have into a form that at least their own students will be able to relate to and progress from.
The case would be stronger however if it were a very well-written self-study/"teach yourself" style book, translated into the student's first language, and with scores of apparently satisfied and successful customers (I guess that Linguaphone, Pimsleur etc are pretty protective of their courses for English people studying whatever languages).
The choice could well be between being a very successful private teacher with some sort of "secret" for success, or selling that secret for others to use.
http://itre.cis.upenn.edu/~myl/language ... 00947.html
http://forums.eslcafe.com/job/viewtopic.php?t=15850
http://forums.eslcafe.com/teacher/viewtopic.php?t=2860
BTW, I notice that you've posted what seems to be an indentical query on not just the AL forum, but three others too, but it's the AL one that gets the most answers if not traffic, and people don't always check to see if they'll be more or less repeating what's been said elsewhere (i.e. it can end up wasteful of people's time). Perhaps redirect people after a while to what seems to have by then become the most productive of the four threads (it is also possible to delete unanswered initial posts and thereby the threads that contain them).