I think it should be fixed, as it is very OP and immersion-breaking, while at the same time pretty hilarious.
If you climb in an enemy APC's back (while both gunner and driver are inside), APC will literally start shooting itself.
Other foot soldiers and tanks will also shoot the vehicle. Freaking teamkillers
What do you think?

I suggest the fix where you can't get inside the vehicle, if there are enemies in it. You can force them out, but you can't get in, unless it is empty.

Real players are the AI's primary targets and bots know their lives are cheap, so you're the most hunted character on the screen.

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