There are multiple issues on the game engine / licensing.
- It sounds like all "open source software" is "problematic". But only copyleft is.
- Link to http://www.blender.org/education-help/faq/gpl-for-artists/ is broken, should be replaced with http://www.blender.org/support/faq/
- The "Distributing Games" section first promises "how to distribute your game with suitable license protection" and then immediately suggest using no license (Which is impossible. It *has* to be GPL, if you compile the game, thus that section should be removed)
- Game Actuator could use more help for people unfamiliar with it.
It appears that the topic is partially covered in section "So I can make games without having to worry about the GPL, right?" of http://www.blender.org/support/faq/
I suggest that the following text is used instead (check for factual correctness required by somebody who knows Blender better than I do):
Restrictions apply to games made with the Standalone Player, as Blender is licensed under the copyleft license GNU GPL.
You own your work made with Blender but when you create an executable for your game, part of the Blender Game Engine gets copied into it, making it a derivative of Blender. GPL requires that derivative to be GPL-licensed.
Instead, you can bundle the Standalone Player and your .blend game without combining the files. Using Game Actuator, enables a basic .blend game file to start. By making a basic file which contains an "Always" sensor to run, and allowing this to activate a "Game" actuator to load and run the full content of your game, this gets round the problem.
The .blend file is not encrypted and readable by anybody who owns the game. You still control what people are allowed to do with your .blend by choosing the terms under which you distribute your game but people will easily be able to study and modify their copy of it.