That will help you win in the end but it won't stop the suit being filed anyway hoping for a quick insurance settlement (they pay out most times).
I've considered the sub route but the pay is pretty bad and you still need GL for snow work and most companies won't write a policy for city or town work. That work pays the best around here for subs. The other problem is the lack of locally owned and operated property. It's all giant corporations and they typically sub to whomever is the cheapest at providing all the services like cleaning, security, and maintenance.