The Big Phat Band don't play Nestico arrangements, no. You could say that they are maybe a 'pop' or 'funk' big band. When you play music like this it will be louder as the backline can't 'tickle' their instruments as the tonal colours won't be right. You won't get that 'thwack'.
Everything else therefore needs to come up and have some help with volume. The arrangement can be bigger overall too with more lines underneath sections with the melody, or even the soloist. It enables more control too of course. In some venues the band would sound absolutely tiny if not fully mic'ed.
It is possible though that some sound engineers then mix and eq the sound as if a rock gig - especially the drum sound and things can spiral way out of touch from the jazz heritage very quickly.
I can't think of any major big band that won't be fully mic'ed these days:
Connick is: amazing band and one of the most talented musician and performer around;
Buble is: now I saw him several years ago and the drum sound was like a rock kit. Pretty nasty;
Ellington Orch: still exists and also plays fully mic'ed.
Jazz At The Licoln Center: Fully mic'ed.
Even Count Basie and his orchestra 1969: Fully mic'ed (but ambiently mic'ed, not close mic'ed.
Mostly, the concert halls would swallow a big band. In fact, Thad Jones/Mel Lewis band are fully mic'ed from the early '80's. Same with the Bob Mintzer band. Point taken that in the instance of the concert by the Big Phat Band at RNCM was a small theatre - but the arrangements wouldn't really work.
Thanks Greg. I was trying to get this over to a student on Monday. Luckily, he does it the same way as me! I call it dead-tonguing - but that might be something else. Dood-n is good and is probably a more universal term.