That only works if you have enough volunteers.  Most people work and don't want to come home to do voluntary security patrols.  There will also be people who will take advantage in gang controlled areas...how do you think the folks that live in those area's are going to feel when the gangs run out the volunteers.  Just way to many different scenario's that would play out to make such a endeavor impossible.

I see lots of societies with taxation, that are doing OK. Some are thriving.

I don't see any society working without taxation?  Any idea why?  Have you thought deeply about what your utopia would really be like?

If your utopia is so wonderful and so obvious, why doesn't it exist already?

Taxation isn't theft if you have representation.  Do some research on the system in Switzerland for taxing.  Still theft in your view?