Who would light the fires though? A Genonese person? Or Tuscanian and even a Lombardese? There's too little info and it's a bit too far in the timeline. Though if I had to guess it would be the Genonese exiles that would probably light it by killing someone important. Hopefully not of Roman Origin but since this TTL, the events of like WW1 would probably happen differently.Or it could pull a Serbia and cause a world war later on. Which would be unfortunate but interesting.
I do like the idea and see how it could work in the short term but also how it lacks the sheer defensible topography that makes Swiss long term neutrality work. Combine that with being a very lucrative goal for any neighboring power to want to incorporate and they could pull a Switzerland impression right up until one of the great powers/alliances enforcing this state of affairs is distracted, disunited, or otherwise unavailable and the other side is good to go, and then boom, either independence lost or massive European war.
Or both. Both is fun.