I've never had a problem bringing guests to the Concierge Lounge with me. I have had hotel restaurants tell me that only I could get a free continental breakfast as a Plat -- and not my son, who was traveling and staying with me. I found that particularly obnoxious, as my son was pretty young at the time and got a children's buffet for $3.95 or so. It seemed quite petty -- and was! But other hotel restaurants have provided free breakfasts to everybody in my party. Of course, I use the restaurant only if the lounge is closed or unavailable.
Bruce