I don’t know whether anybody spoke to them about it at the event, but I intend to mention it to the conference organisers. I assume there will be some form of post-conference feedback; if there isn’t, I’ll drop them an email.

While I can see that both could come from the same place, in practice I think that the chippy chappie with the lefty politics was attempting to provoke a reaction in his audience, whereas the German with the kerb-crawler slide felt that it was a suitable illustration of the point that he was making.