My thinking is that, should I have the misfortune to deal with this service, I'll be tipping the SCA per normal and leave it at that if in my room. If in the lounge...well, this gets tricky since there's likely to not be a CC transaction to slip the tip on, so either I'll have a single or a dollar coin or...well, sorry, but I'm not inclined to bother much beyond that. No offense to the staff, but where I tip for the diner staff I do so in consideration of the fact that it's several people giving me at-seat service.