Passing off keyboards as something else

In these vids, the artist attempts to pass off keyboards as brass. Why do it? I don’t remember this phenom that well. Was this a common thing? Did anyone else do it?

Don Henley All She Wants to do is Dance (after 00:20)

Roxy Music More Than This (after 1:08)

Nitpick: A saxophone is not a brass instrument. It’s a woodwind.

I would have to guess that it’s just cooler watching someone fake play a sax or trombone than a keyboard (especially the kind that slings around your neck).

Point taken, but did they think they were fooling anyone?