I would not do it. I doubt that it will make much difference.
+1 We're interested in knowing that applicants understand they'll need to publish while in grad school, and that they can complete and submit a proposal. Unless this is a really really big-deal conference in your field, we don't really care a lot about whether or not someone has accepted it at this point. (Some conferences in my field are so thin that anything written in complete sentences with most of the words spelled correctly will be accepted -- but still, the ability and self-confidence to complete and submit a proposal is what matters.)