I don't think the person who went outside of the room for the group photo is clearly visible on one of your photos, so I don't expect there to be a practical problem with the photos that's you posted.
On the other hand going forward I would want to have a system that allows people to clearly signal that the don't want to have photos taken of themselves.
From the LessWrong regulars, if gwern would attend a meetup I would guess that he would be uncomfortable with photos of him afterwards being available online.
While being a toastmaster I remember having a board member of my local toastmasters club who didn't want picture of him on the internet because he had a public persona as a musician and didn't want the information of being in a toastmasters club associated with that persona.
The European Community Weekend in Berlin is over and was a full sucess.
This is no report of the event but a place where you can e.g. comment on the event, link to photos or what else you want to share.
I'm not the organizer of the Meetup but I have been there and for me it was a great event. Meeting many energetic, compassionate and in general awesome, people. Great presentations and workshops. And a very awesome positive athmosphere.
Cheers to all participants!
Gunnar
PS. I get it that there will be an upload of the presentations by the organizers and maybe some report of the results some time later. Those may or may not be linked from this post.