True. But the rules for collision avoidance during a turn are simple - follow the leader and maintain the same relative distance and "angle off" with respect to all the vehicles around you as you turn.

Certainly the calculations required for such changes of direction already exist since those algorithms are commonly used to simulate the behavior of groups of birds, fish and herd animals.

I'd also consider it to be realistic if a sharp turn at high speeds results in collisions, or vehicles skidding, stalling, tipping over or temporarily losing formation.

If IL2 can't handle the sort of math required for perfect station-keeping and collision avoidance, parameters could be built into the formation to limit the maximum speed and direction at which the formation can travel to make collisions or unrealistic behavior impossible. Again, this is realistic, since groups of disparate vehicles in convoys have to travel at a bit less than the highest sustainable speed of the slowest vehicle in the formation and formation leaders need to take the limitations of the least maneuverable vehicle in the group into account when making maneuvers.