Correct me if I'm wrong, but I interpret this:
  Activities other than copying, distribution and modification are not
  covered by this License; they are outside its scope.
as meaning that compilation and execution are not covered.

Adding a requirement to click one or another button
in order to be permitted to compile or execute would
be outside the scope of the GPL.

On 2 Aug 2002, David Mandala wrote:

> I'm sorry the GPL does not just cover redistribution it covers use of
> the software too. There is no reason why a click-wrap license could not
> be applied to the GPL or any other license.