This year I got to spend a paltry 5 days in the Magee Marsh in Ohio, during the beginning of the Biggest Week in American Birding. Next year I plan to stay for the entire 2-weekend 10-day event. I can't believe how close the warblers were, though not one person I encountered used recordings or even pished. I was there before the peak, so a handful of people were complaining that it wasn't "good" yet, but every moment was sheer joy for me.
There are a huge number of people filling the boardwalk, so it does get a little overwhelming. But I loved how the people were held to the boardwalk while the birds roamed about, and the way I figure, the more people who love warblers, the better the future for humans and warblers both.