Yeah seen that Apple is doing that for Epic's Fortnight. Won't be able to sign for Mac, but people could still install it if they turn off gatekeeper which I doubt many people would mess with, been a while since I've done that myself since I use dev tools. I think now on Catalina and newer Mac versions even more steps. Used to be a checkbox, but I think you have to use the terminal now?

Never really worked with Unreal but wonder if this will affect other games using their engine, not sure if there's like signed dylibs and stuff.

All this security stuff is cool but in a way more control. It's like you paid all this money for something but in a way you don't really own it. Like some graphic card company sells graphic cards including server graphic cards, but their driver's EULA doesn't allow you to use your desktop cards for server use. I guess the hardware being used 24/7 wasn't designed for that, but sounds like they should deny your warranty then instead of turning it into a copyright issue. Some game streaming company ran into this problem.