The neighbors know what they are talking about in terms of there being Anonymous involvement. The neighbors are on scene, they've seen it.
"No evidence"? You need to do a lot more research. There is multitudinous amount of evidence. This was organized for months prior to the start on Sept 17. The professional organizers were exchanging emails on this back as early as March. They worked on this in Spain and thought they could do something similar here. Anonymous came on board officially in August with a "OWS Message" video not unlike their "Message to Scientology" video. They have been posting on the Anonymous protest website about involvement in OWS since the beginning. You can see involvement of Anon in many of the protests-hence the Guy Fawkes mask involvement, which is an anon symbol to protect identity(first used in the protests of Scientology). That's why the mask is there.
Anon's part, at least in the beginning of this "occupation" didn't just involve providing bodies, but also were involved in a DDOS attack on the NYSE. Google Anonymous and NYSE attack and you can pull up the Forbes account of the attack which really didn't do much. It was Anon that figured out the identitiy of Officer Bologna in the pepper spray incident. The have hacked police sites in several cities and leaked police information, in support of OWS and been threatening sitll further action. Anon involvement is even listed on its Wikipedia page. Google Anonymous and OWS to read more about its involvement.
Think of Anonymous as sort of a big umbrella term. 1. You have those that protest Scientology. 2. You have those that were involved in attacking Pay Pal and Visa, Wikileaks, Anti Sec and Lulzsec spinoffs. This second group spun off some who are involved in OWS, this includes AnonOps that was involved in most of Wikileaks, PayPal DDOS actions. But also involved in DDOS in support in Tunisia and the Arab Spring. This is a relatively small contingent, but was, in part, responsible for many of the initial bodies coming out in the various cities (other people, as I have said before were a mix of professional activists, who are really the ideological control, and college kids that just want to improve things).
The bigger part of Anonymous, the third group, such as those on 4 chan, think all the protests are stupid and despise the first two groups as being lame. They are actually very much against OWS and have trolled OWS. Most of the people involved in the first group as well have nothing to do with OWS as well.