Should a runner sleep in the van/crewing vehicle?

[TrailTramp]

All I gotta say is I'm among very lucky people this year to have at my disposal  Daus-Weber and Jones' crewing guide - if you don't have one, get one - a steal for a mere $20.  

I have a question as to where it is apppropriate for the runner to sleep during the race.
 
Chapter 6:  Crewing During the Event, Section 6.4.1, "Planned Rest And Recovery Breaks,"  pp 55-58 discusses the need for rest and recovery breaks for runner (and pacer) and specifically addresses on-course breaks.

I recall being advised by a Badwater finisher last year that under no circumstances should a runner be allowed to sleep in the van/crewing vehicle, although non-sleeping rest is permitted.

However, page 57 of the DV Guide, in Table 6: Planned Break Activities and Required Supplies states that the runner may "lay or sit inside the running van with the air conditioner on, being sure the runner doesn't lay flat and being sure the head is higher than the heart to prevent losing consciousness due to a rapid change in blood pressure and flow."  It lists an alternative:  "sit in a lawn chair under any possible shade provided by the van."

Okay.  Of course the runner will need to rest, and if a shaded area in a lawn chair doesn't do the job of adequately cooling off the runner and air conditioning will, and then sleep is the only thing that will make the runner feel better, if the sleep is not too long, what are the concerns letting the runner sleep in the vehicle?

It seems to me, and I would like to hear people's input about this, that if sleeping in the van gets the runner back on the course feeling better after being cooled and rested, isn't that what we're trying to achieve?  

I'd like to hear opinions on both sides of the fence here.  Are there others out there who don't recommend sleeping in the van and why?

Thanks,

Connie Karras