In regards to both Edge and Batista going on social media and suggesting that they were not invited or not coming to The Smackdown 1000th episode next month, often when wrestlers publicly do this they end up being there. However, it should also be noted that due to the way WWE works, a lot of wrestlers who are brought in for these special type shows aren’t told anything until just before the show so sometimes when they say that they aren’t invited or have no idea it is in fact an honest statement as WWE at that point in time hasn’t approached them.
 
According to a recent article in The Wrestling Observer Newsletter, the reason for this is because not only does WWE not plan their TV shows out much in advance, usually only a few weeks ahead of time, but if they invite wrestlers well ahead of the show’s date, there is a much greater chance that the news of their appearance will leak out before the company has had a chance to announce it through their own channels.
 
With Smackdown 1000 still several weeks away and a couple of big shows between now and then still on the docket, WWE still likely has a list of talent that they will be approaching for the show and many of them have no knowledge of this whatsoever.
Source: Wrestling Observer Newsletter