Installing a cabin-based alternate air is a good thing, does add one more place for a leak....but at least an easy one to find and we do build to suit, and making ourselves comfortable in the cockpit with equipment AND the right skill set is ours alone to implement. I did not install a cabin static vent on my 10 due to having the redundancy in back, the location, and the ability in the 10 to easily make it a self-draining system. Water build up in the line is extremely difficult to imagine how it can occur. Not to mention we pretty much all have GPS readouts of altitude that are 100% independent from the static ports. On the list of instruments I have lost during IMC flight, static port blockage is the easiest to deal with, ONCE RECOGNIZED. Lets face it, some really serious commercial crashes are due to autopilots/pilots making single instrument focused death dives in what were perfectly flying aircraft with engines purring along or not, they still glide quite well when kept upright....
Dues paid 2017
RV7 built & sold, 500h of pure joy in the air: sold
RV10 slow build & flying & loving it