This. But have different versions of them. Crowds that dance and sit stationary, crowds that talk to each other. Or even a singular npc just standing or doing whatever. Just for the sake of making the eventlabs feel a bit more lively. Id be a nice touch to anyone making city eventlabs.
And now especially with the addition of the car park props we could be able to make car meets.
Great idea. But I think it doesn’t match with Forza’s way of “pedestrian and spectator protection system”. What do I mean by that? All NPC’s in Forza Horizon are hidden behind some kind of barriers so that they can’t be hit by the player cars. Therefore I think it wouldn’t be possible to place NPC’s one by one. But maybe in their “protection boxes” so you can place them at the side of the track like in the existing vanilla races in the game? I would also appreciate the grandstands being filled with spectators. At least having the option to chose an empty grandstand as well as a crowded one would be great.
Spectators are animated. That could be a performance problem if you place to many of them. Maybe a smart calculation system could be implemented which gives you warnings such as “this creation could be problematic on XBOX One consoles” or something like that.
But the idea of adding people to the eventlab props is a great one. 
NPC can have an invisible cube. This way, nothing can hit it.
We can have 2 options for crowds:
1- animation enabled: this will fill the maximum budget quicker.
2- animation disabled: this will fill the maximum budget slower that the first option.