I am not so sure that Autodesk has any legal or moral right to prevent the development or application of third party software.
On a moral (or what is right) lets look at it a little bit deeper.
If you do mechanical design using plain AutoCAD then isi it right to not purchase MDT? I don't think anyone would argue that you should particularly if the plain package suits most of your needs. So what about LDD? Should you not buy plain AutoCAD if you are going to do civil work? What about all of those lisp and vba routines that do essentially the same thing as LDD, ADT, and MDT? Is it right that you should use them instead of buying the appropriate development package from Autodesk?
I see this as a ploy to force people to purchase the programs they want you to use and in the end create great wealth for the company. If I were a shareholder I might think that was a good idea until I realized that there are really about 3 different scenrios that could take place.
1) Users will be forced to purchase full blown AutoCAD and will bite the bullet.
2) Users will continue with the "unauthorized" activity
3) Users will use a different development package, such as IntelliCAD
I suspect that the largest majority of the users of LT will take option #2 and #3
The "right" thing to do would be for Autodesk to drop pending lawsuits (if they are still pending ... that was Oct 2003) and embrace the ingenuity and development of more third party applications.
The simple fact is that anyone with a little bit of windows programming knowledge can write programming that will work with any program, regardless of whether the original developer ever intended it to work that way or not. If I wanted to write a program to draw a box in LT, I could write an API that would identify the command line window and simply put the desired commands there. It would neither infringe upon the copyright or licensing agreement of AutoCAD because it would not use AutoCAD code. It would use only the base functionality of windows commands.
Quite honestly I am proud that I continually produce software that works with AutoCAD, extending it's capabilities beyond that which Autodesk originally designed. In my line of work, if I were to purchase the Autodesk software using the premise that it is not "right" to develop applications that are not within the intent of use of the program, then I would be morally obligated to buy LDD, ADT, MDT and Inventor .... Clearly this is NOT what I am doing and nor will I. Sure there are functions in those packages that would make my life a bit easier, but I can develop a similar command or purchase one without too much hassle if I need to.
I support the actions of LT-Extender as a viable option to the overpriced software we now currently are relegated to use.