It's specifically for retailers. But they have a bunch of publishers come out to show off their games to retailers. Back in 2014 info for the new CoD (Advanced Warfare) leaked out from there. And Rockstar was planned to be there that year but pulled out at the last second, attendees then said to expect an E3 announcement from them. And sure enough we got GTAV current-gen from them announced during Sony's conference. So, Sony has plugged the holes pretty well since then and not much has leaked out. It's a pretty airtight with the most you can hope for is that some retailer attending drops some meat. But even that is unlikely.