I have seen JWs attend weddings of non-JW relatives held in churches. These same JWs will turn around and cast judgement on other JWs who wish to attend the weddings of their own non-baptized children, held outdoors or in a civil ceremony officiated by a justice of the peace.
It's appalling the way so many JWs boycott these happy occasions. When you think about it, if any of these people originally RSVP'd and agreed to attend the reception, the family planned for and arranged for and paid for meals for these people who later ended up being pressured to boycott the wedding.
I have a JW brother-in-law who insisted that all the deli meat at a cold buffet style wedding reception be thrown away, and went around telling everyone in attendance not to eat the meat. Why? The bride's parents - who were hosting the reception - were not JWs, but the bride had recently been baptized in order to marry a brother in the congregation. My BIL insulted the bride's parents by assuming that they deliberately purchased deli meat that had blood (aka "by-products") in it.
Even as a true-blue JW back then, I was mortified for the bride's family. My BIL is such an @$$.
Love, Scully