Quote:Original post by Evil SteveNo - not only is it a violation of the EULA, it's also a security concern.
The reason the D3DX library was moved into a DLL was so that it can be patched via Windows Update, in case a security problem is found. If you always overwrite the version on the user's machine with your version, then you might be overwriting a newer, patched version of the DLL with a broken version. Like wise, if you put the DLL in your application's working directory, then the OS will load that one instead of the potentially patched one.
Though if he included his own DLLs, he'd be pretty unlikely to install them in the system folder, adding a D3DX DLL in your application folder has no effect on the rest of the system, merely prevents him from taking advantage of future updates to the dll.