Don't worry, this kind of love letters will become the rule as it is in Ryanair. There you can only take 300 kg extra without giving a serious explanation and when I say serious it must be serious. Also in FR there is a fuel league, based on real burn against plog burn, I can tell you that those pilots at the bottom of the league receive this kind of letters.
I guess as more and more Fr Jockey's are joining EK it will not chock them more than that.