Sadly no. You CAN assign a scene to each user, which is loaded when they log in, but it ONLY gets loaded when you actually DO log in. So if you shut it down as user Fred, then when you power up again it is still logged in as Fred and the scene DOESN’t get loaded. SO you might as well load the scene as log in.
What we do is use some of the softkeys to load standard scenes, and then we always try to remember to load the default scene before we shut down. But if someone forgets, it is only a matter of pressing the softkey.
While it sounds attractive to have a default scene on startup, I can see it being a real pain in the scenario where there is a momentary power failure causing a reboot. You would loose all your settings. Similarly if you forgot to save a scene before powering down, and you were expecting everything to be as it was when you turn it on again.
In this respect it behaves like an analogue mixer would, which is what people kind of expect.