I think it may be smarter to limit the amount of objects that can be spawned by a player.

Yeah, same here. Feels like it tries to download the mods of another server. When trying again it works.

+1, should be a standard for any games having night time.

Same here. Happened to me once.

You're talking about ARMA 3's "ctrl" feature where holding control would let us change our pose with WASD? I'd love it back yeah.

Maybe instead require to remove occupant of a seat before letting the player entering the seat at all?

Same thing can be said with the park brake.
We remove it when we enter the vehicle, but never put it on when exiting. And if the driver gets killed and the vehicle stops, is the parking brake on again when another player goes in the driver seat?