Queens grill your butler will serve tea/coffee any time you want it free you also get 2 bottles spirits /wine/beer free .
We were in the Princess Grill and the accommodation was excellent no problem over coffee but we always tipped the person who brought it, but no charge. As you are in the Queens Grill you will have your own dining room and we found the entertainers also dined there sometime alternating between the Queens Grill and the Princell Grill. We had Jim Bowen and wife; Jenny Bond and family; Trevor Sorbet the hairdresser and a few more whose names I can't remember but it might not be this on your cruise.
Room service is 24 hours and its free and fantastic.
Queens Grill Cunard , well you've paid enough already so you DON'T have to tip each and every time you request somthing in your suite.. your Butler will always be on hand ( and does not expect tips every time you request somthing) all you do is pick up the phone.. .After hours you still pick up the phone for anything and a night steward will attend to all your needs... Regarding entertainers who may have dined there, maybe very top entertainers might do if Cunard has invited them and if there are any spare tables... It's not a staff canteen even the Commodore does not have a table there. Just sit back and enjoy 5+* service.