Actually, I did send in a friendly "complaint" about a bad lounge situation at an EU airport (IE passengers directed to an overcrowded PP type lounge) direct to somebody higher in the SQ organization in the country. Never got a reaction, though, when flying SQ 2 months later, SQ did direct passengers to a significantly better lounge. Of course, it could be, this was already realized, and I just had missed that change, or it was already in the works before I complained.....