When Stelios Yamalis and his mother, Fedra, arrived at Madison Square Garden on Tuesday night for Game 1 of the Eastern Conference finals, they found blue T-shirts — “Always Knicks” splashed across the front, a corporate sponsor logo on the sleeve — draped over the backs of their seats.

Identical shirts had been placed on each of the 20,000 or so other seats, and the suggestion was clear: Wouldn’t it look cool if everybody put this on?

As far as Mr. Yamalis was concerned, he was already in uniform. He had on a two-piece suit crowded with mini Knicks logos. His mom sported a blue sequin jacket he had gotten her for Christmas.

The notion that they would cover these outfits with a shapeless, extra-large shirt felt absurd.

“When you put the T-shirt on, everybody looks the same,” said Mr. Yamalis, 24, an engineer from Ronkonkoma, on Long Island. “We’re New Yorkers. We’re all different kinds of people, in different kinds of ways.”

The T-shirt giveaway has become a staple of the N.B.A. postseason, with teams across the country engineering monochromatic backdrops to elevate the atmospheres inside their arenas. Fans of the San Antonio Spurs, the Oklahoma City Thunder and the Cleveland Cavaliers — three of the four remaining teams — have embraced the shirts this postseason with enthusiasm.