Its not a demo though. And people will be reminded 24/7 when they are orks, they are not paying customers and do not recieve half as much stuff
I would not mind advertisements. Just as long as they ten me what I need to know like where to get some good mjod and a good cutting stone for my axe.
One of the biggest selling points about 40k is an environment which is completely immersive and lore so rich that it makes the idea of the warp and alien races battling for tens of thousands of years believable. Having something like a texas hold em' website ad pop up now and then would be devastatingly effective at taking me out of that immersion. I am really hoping not to see any sort of thing occurring in the game.
No need for advertisement in the game it self, it would just serve to scare players away, welcome someone in and push advertisement all over the player, it takes little to make someone convinced you are here only for a money grab.
The Free 2 Play mode is pretty much a demo where you're restricted to 1/8 of the playable classes and not allowed to progress past a certain level. I'm pretty certain some subtle (or not so subtle) advertisement will be on the Free 2 Play mode for the full game.