The “four kinds of freedom”, as defined by the Free Software Foundation, tells us that users of free software have “the freedom to run the program, for any purpose (freedom 0)”. What an irony it is then, that most open source/free software applications I have installed on my Mac include a licence agreement step, like in these pictures:
The user cannot install the software without agreeing to the GPL, which I must say is a clear violation of “freedom to run the program, for any purpose”. And this is regardless of that the GPL, to the best of my knowledge, does not impose any restrictions on the user of a GPL’ed application*, so there isn’t really anything to accept.
Edit: The GPL FAQ actually mentions this.
* As far as I understand it (I really need to say that so that Stallman doesn’t put a fatwa on me), the GPL is concerned with distribution of software, not, for example, usage.