fashionably late

米国では家に招待された時に早めに行ったりせず、むしろ若干遅れる方が良いと聞いたことがありますが、その少し遅れて行くことを示す表現がTom Clancy's Net Forceに出てきました。
Maj sighed. "Okay," she said. "I'll go. I'm free tomorrow night fortunately. Where are we going to meet?"
"A public site," Fergal said. "I'll drop you the address. Roddy's playroom opens up at twenty hundred We'll be fashionably late."
普通の辞書にはこの "fashionably late" の説明は中々見つかりませんが、俗語に詳しい次の辞書に説明がありました。
・Urban Dictionary: The refined art of being just late enough (5 minutes or so) to give the impression that you are a busy, popular person that was held up with other business.: She arrived at the party fashionably late.
Googleで検索すると同名の曲もあることが分かります。