I was traveling Friday June 20th on the red-eye flight UA#84 Lax-Ewr on first class. I am not an RCC member, I am an Amex Platinum credit card holder to access DL & CO clubs which are the airlines I mostly fly. Flight#84 was delayed, so I went to the RCC asked the receptonist if I can come in. She said this is a club for members only. I said I understand, but my flight has been delayed and I would like to have a drink and make a few phones and I really would appreciate her kindness if she would grant me access. She said please come in I hope you like our club. On my way out the club I stopped her desk and again thanked her.
Bottom line the answer is yes.