In an ideal world, Centurion Lounges would be able to accommodate as many visitors as needed. In reality, overcrawding is an issue at most of the Amex lounges I have visited. I was getting ready to visit the SFO lounge when I noticed that not only will I need to do a check-in on the app, but I also can not access the lounge at landing or come in 3 hours before my flight. While I understand the need for these restrictions, this lounge has always been ideal for me as a United-hub-prisoner since the sole Priority Pass lounge is located on Terminal A. These restrictions do make the allure of Centurion Lounges at lot less appealing thus affecting Amex’s competive advantage.