Being a VW fan as well I used to ride the sand dunes in a friends sand buggy, and BOY, did it kick up some sand! The engine was fine despite all of that sand, and it ran properly because of the big foam filters on the dual carbs.
In other words, if nothing got past the air filter, you are fine.
If you can drive through all of that sand with proper air filters without harming an engine, then just sitting there can't hurt either...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car