Originally Posted by
rickyriver
From my limited experience with the Executive lounge with Marriott (and Hilton), they never check anything. You will either need your room key to access the executive floor where the lounge is, or need your room key to unlock the lounge door. Either way, once your are there, they kind of assume you have the access. It's kind of an honor system.
Renaissance LAX and LAS have a book for guests to sign into the lounge. Renaissance LAX also has a placard stating that they will charge extra for any non-hotel guests who come into the lounge (it was something like $30/day a few years ago).