[adam]

Riko nailed it; very much like Tom Green's Freddy Got Fingered:

A situation that was funny on the show (for instance, him acting like a total jackass in a real bank) worked because it was real life...and a similar scene recreated with actors on a set was totally pointless.

It could work; the Borat character is funny, but if they just try and re-create the show's humour, it won't work. It needs to be something else entirely, and they may not recognize that.