Thanks for the tips. I use my own collision detection so that things like bounding box settings won't interfere I figured it out:

As a bit of a place-holder until a future visual update, the "flag" for the new Hold the Flag mutator is just a bitmap of an exclamation mark, and its job is to spin on the spot, or spin above whichever car has the "flag".

It doesn't have its own action -- its spinning and position is handled by an external function using a global pointer. But on disconnect, the entity was being removed without the global pointer being set to NULL. So everything that was meant to happen to the exclamation mark was instead happening to whatever entity was created at that place in memory the next time the client connected to someone.

The video was an online test -- the flag was only being updated when its status changed, and the car was regularly receiving updates from the server, hence its ability to still drive around. Finally, even though the physics are currently all 2D, the collision detection function is working in 3D -- so when the floating orange car bumps into the red car, some of the force is down. The server doesn't care about vertical position, so the red car on the host isn't affected by the regular status updates and is allowed to fall through the ground.

All fixed, now

For slightly complicated reasons the K:D ratio and extra stats won't come in this version. They'd be quite difficult to implement now, and not much trouble at all later when online games are in defined rounds with limits (to the update after this, I'm thinking).

I just need to make and implement local markers, and then a new version should be ready.

Jibb