[Discussion on this proposal is welcomed.--ES]
Let us launch an "Online Petition in Support of the Gendered Conference Campaign".
Signatories commit themselves
(1) not to keynote at conferences at which women are clearly underrepresented;
(2) not to organize male-only or male-almost-only conferences or workshops;
(3) to add to their websites and email signatures the following line: "I am a signatory of the 'Online Petition in Support of the Gendered Conference Campaign'; please visit [Online Petition] for details;"
(4) to email information about the Online Petition and the GCC to their colleagues within and outwith their own department, possibly including various internet discussion lists, blogs, etc.
I would be curious to see how far one could get with this more gentle approach -- more in keeping with the GCC.
(Apologies for this being a one-off contribution. Family commitments take priority for me at the moment.)