Leaving the race early

The only HIM I ever did was coupled with a sprint (no oly).  They did make the sprinters wait around until all HIM athletes were off the bike and on the run, which was over 4 hours for the last of them.  I felt kind of bad for the sprinters, some of who had to wait close to 3 hours to get their gear and go home.  As long as no one gets in my way during T2, I don't care what they're doing in there.

In the race I did last weekend you couldn't get your bike till the last rider was in.  And IMO that should be the norm for races.  But in multi distace races, you realy can't expect say a sprint distance athlete to wait till all the HIM bikers are in, so the transition area sohould be thought out well so that finished sprinters shouldn't interfer with the HIM racers.  In one multidistance race I did there was a volunteer at the bike in, and when a HIM biker came in he would yell out "BIKER INCOMING".  The finished shorter racers would then look up and try and be clear of the incoming biker.  It was quite effective and necessary seeing as many of the early finisher were clustering in the transition area shooting the breeze.

I almost guessed "Indianapolis" when I read your post (and I did confirm with your list of races) as that was very similar to my experience with the tri-series.  My brother and I met up in Indy to do one of the series races in 2006.  Most of the participants were all business and the last few awards were presented in a nearly empty hall.  Not at all like most of my other triathlon experiences where people hang out. 

At Steelhead, nobody (and we held up one of the female pro's) got back into transition until the last cyclist was in because that is still part of the course, and they didn't want someone leaving to impede someone racing (which is a concern if you have 500 people trying to leave at once). 

This is tricky.  I've had to fight my way through finished sprinters, when I'm racing an Oly.  I've also been forced to wait what seems an excessive amount of time to get my stuff (Irongirl Duathlon, where I finished more than an hour before the last biker returned!).  I've also been the person who, tired from the race and not paying attention, got in the way of a racer. 

I imagine there's a good way to do this and it's partly the responsibility of the race management and partly of the racer.  I think perhaps a controlled entrance just for folks wanting to pack up would help.  It reminds the ones leaving of the gravity of being quick/careful, but still allows some flexibility.  There could be a limit of x number of people per time, and they could be asked to keep it quick.

More than once I've been at races where they could have easily opened up a new exit from transition, leading the folks leaving away from the racers trying to run out.  That would have been nice, and I even suggested it to one RD where this is a particular problem.