I live in an OOT community and have a son getting married this week in NYC.
The idea of rabbonim forbidding OOT's from attending a NY wedding is laughable. First, the Tristate rabbonim (yeshivish circles) have moved on. The only potential incentive for them to prevent OOT from attending would be if they believed it was halachically warranted AND it was protecting the NY-area residents. Certainly once the initial wave passed, many Rabbonim did not believe it was halachically warranted to shut down or limit communal life. Adding to that, Tristate-area frum circles have achieved herd immunity (whether real or imagined, practically it is the same). Secondly, the number of OOT that will actually attend is very limited even without the Rabbonim getting involved, at least in our case and all those I have spoken to that are in our shoes. A large percentage of friends and older family members from OOT are regrettably (not a Covid editorial, but personally) not going to be attending. The majority of the OOT attendees will be the friends of the chason and kallah and they have been to countless weddings in the last 3 months and have been in camps and yeshivos without recent infections, so are unlikely to be newly infected. Third, law or not, people are traveling to/from NY for business, pleasure, family, etc. from OOT for multiple days and the quarantine laws are just not relevant. It is hypocritical that the law becomes a factor for Tristate weddings and not for other 'illegal' travel.
The fact is, as stated by by several commentors, those returning from weddings that are newly infected have not lead to known community spread. The proof is in the pudding, so to speak, that OOT weddings are not leading to detectable community transmission.