No. Lounge attendants know nothing about your Priority Pass membership, and there are many variations: paid, sponsored; unlimited visits, limited visits, pay for every visit; free guests, paid guests etc. All the lounge does is scan the card and record the number of guests (if any).
However, Priority Pass has also added restaurants, and memberships sponsored by American Express are not valid at those locations. The restaurant knows this, and may ask if who sponsors yours. In this regard, a membership sponsored by American Express is inferior to those offered by other banks.
Thanks for the great reply! Yeah, I've heard about the downgrade where restaurants are no longer paid for by Amex. Luckily, I have both Amex Plat and CSR.
So, is there some way to offer to pay for lounge access if one has a Priority Pass membership that lets one in for free? I do have another membership (through a Marriott-owned timeshare program) that includes pay-per-day Priority Pass membership. However, I have never bothered to get a paid Priority Pass membership, and I doubt I have time to get a card for the paid program before my trip.
And, if I take it correctly, my Amex Plat card doesn't help in any way with getting into a Priority Pass lounge?