Having participated in and organised 5 EA Play, E3 and Gamescom events now, you really don't want to be playing most games at home, based on what is shown at the events and the work that goes into those.
Speaking only for Battlefield, progression, online services and any sort of persistence is removed as the backend services are usually neither ready nor up to scale, if we were to somehow get them ready on time. So our events are done on local servers running very specialised event-only software with no UI, no FrontEnd, and clients connect directly on the server via direct IP and port usage.
Games have tendencies to crash or hang or whatever. In the Gamescom demo last year where we were showing off RTX, we had a nasty crash where if a grenade is thrown through a very specific window, everyone on the server would crash. Only happened a few times, but that meant that we had to reboot 64 clients in matter of seconds so that people don't get angry that their play session just ended.
While we ourselves do not do any special hacks and fake things, and I am super proud of what we've done over the years with how we've improved our event management and setup, where last year we likely had the biggest ever single game setup at a conference like the above with 256 PC and 40 Xbox clients and got several thousands of people to play the game, I really wouldn't give that experience to folks at home, as simply it is not reliable. :)
Not to mention, how many games actually fake things, including creating whole levels or experiences literally to just show the game (a complete throwaway work in terms of time and costs) at an event in the best possible light. :)
