My initial thought was similar to Lavender's. Sometimes it seems as if those close to me were better able to accept me when I fully made it clear that I was not ever coming back. For me, that was explaining that my issue was with the bible in general. Oddly, I was more of a threat when I didn't believe in their specific doctrines than when I didn't believe in the bible or religion in general. It wasn't until that was clearly marked that they were able to begin accepting me. That said, I am not DF'd so there are no clear rules against me.
For some, I think that as long as they see a chance that their shunning or "arms length" strategies are working, they will keep them up and perhaps strengthen them. Because ultimately they do want you "in" where you can be close to them without them getting in trouble.
My thoughts (considering my range of experience) would be to not go, unless I was planning to go often enough to become reinstated and then fade right after. Playing the system so to say. Otherwise, I'd be more inclined of drawing clear lines of where I stand and expecting them to accept me as I am.
All that said, you know yourself and your family the best and it really only matters what you think is best.