Have you ever installed software such as the macromedia shockwave plug in only to be tricked into installing something you didn't want?
Isn't it weird that in most cases, the tick box or radio button is almost always selected? Have you ever quickly gone through an installation without reading the small print and ended up with yet another free toolbar in your browser?
I personally feel that this type of promotion is wrong. An installer should only have the software its meant to install, and nothing else. If an installer has other software included with it, it will obviously make the file that you download larger than normal. This may not sound like a big deal to broadband users, but dial-up users will explain how an extra few kilobytes can slow down the download.
This technique of promotion makes the company look desperate, because they resorted to this method because another method was not effective enough.