Hurst hates hearing poor renditions of the recit.
It's in the back of the simandl, and everyone learns it, so it can be tiring to hear it for the 4000th time, but I can tell you why it is a good lick to play for an audition:
1) It shows off aspects of musical personality that aren't evident in licks of running 8th notes - the students ability to understand phrases, what else is going on in the piece besides the bass, the students current dynamic envelope.
2) It takes a lot of bow control to play it well under pressure - If you can do this, it's impressive. If you can show that you have the type of bow technique that is already making very musical ideas from the notes on the page, it will not be to your detriment.
3) Vibrato - a big chunk of time will spent on vibrato in your first couple years if you don't have it already. If you have a good strong vibrato and can keep it going between notes then its going to show well on this lick.
I would say that your best bet is to find the excerpts your son can play the best (in terms of technique, musicianship, and sound) and present those. Do make sure to present an excerpt with some type of off the string articulations, though.
Honestly, at this point in the game Hurst has heard everything and everyone and he isn't going to hold it against you if your playing a warhorse, as long as you play the crap out of it.