I have been flying models since the 60s and 2.4 since 2006. That said my experience sides with Dirtybird because in 2007 I in fact setup a two battery system in a 40% gas model hooked up to a single switch providing power to a single 2.4 receiver and ignition module on the same circuit as a test bed. I have also flown that airplane and setup 100s of flights without a single hiccup, so just my own experience on the subject. Can 2.4 be hit, who knows for sure. My advice is to setup your airplane using best shop practices and get your own experience.

Bob