PetrW: But I think your question was mainly directed at whether Christ was somehow deliberately hiding the time of His coming.
I was trying to show a flaw in the JW approach. The concept of an invisible presence seems odd until one learns of the attempts to set dates in the 1840s and 1914. In both of those situations, the concept of an invisible presence was used as a way to imply that the prediction had not been completely incorrect. The claim was that the event (Christ returning) had indeed occurred, but it had happened so quietly that even those who expected it hadn't noticed.
It's the sort of obvious nonsense that we normally see through, when the stakes aren't as high as we believe them to be. If our hopes and dreams are dependent on a prediction coming true, we are willing to extend our credulity surprisingly far.