Amex is a sponsor at the US Open (Tennis) this week and is running two lounges: A general one for Card holders and a Centurion for Plats and Cents.

The Cent lounge is 2 total guests for Platinum, 4 total for Centurion card holders, but requests had to be made via Resy due to very limited capacity. They mentioned a waitlist online or in-person at the event. Access is for 1 hour for either Plat or Centurion card holders.

The other lounge seems to be walk in "With up to 2 Guests" but it's unclear if that's Cardholder +2 guests of that person or Cardholder +1 is 2 guests of the lounge.

Resy is an interesting approach for a resource with limited capacity. Hopefully it doesn't turn up somewhere else. It's not like air travel can always have a consistent schedule.

I'm not at the event, just looking at the url usopen.org/amex.