Someone provided the following feature that can be turned on and off:
Here's what the VW owners manual says:
1. Place key fob in ignition switch
2. Cycle ignition switch on/off 5 times ending in the on position (don't start engine).
3. Within 10 seconds of final cycle press hazard switch.
4. A single chime will sound to signify procedure was successful.
This will turn on or turn off the hazard flash when sliding doors are opened.
I just tried this on my 2010 SE and it worked. I had turned off this feature when I bought the van, and had forgotten about it. I think I'll leave it on now.
They also made a suggestion to create a list of programmable features for the Routan. Please post what programmable features you know of and the respective details about said feature.