A JW explains how their group can tell Jesus returned 'invisibly' on another discussion board:
You are right that you would probably need to be one of Jehovah's Witnesses to see all the things that we see. Jehovah's Witnesses study the Bible in ways that a lot of other people don't. We dig into it, read it, understand and see meaning in scriptures that for a lot of people don't make much sense.
There isn't one scripture that convinces us that the sign of Jesus presence is here. There are many, and them taken together are convincing. But for me to convince you of that within a few words it would be difficult. You would need a deep understanding of the various scriptures of the Bible in order to really see what the Bible is talking about. True there have always been wars. Not on the scale that we have had since 1914.
I wonder if this JW would like to 'study' the Bible with any of us in order to 'help' us understand it in ways that a lot of other people don't.