[walrus01]

90 degree inclination all converge over the poles. The dead Russian satellite that collided with an iridium satellite a few years ago is a good example.

[dragonwriter]

Any two circular orbits of equal radius are either identical (potentially excluding direction) or intersects at two points.

which two points is irrelevant to the chance of collision.

[russdill]

To prove the to yourself, tilt the Earth by 30 degrees. Some 90 degree inclination orbits are now 60, some still 90, and the rest in-between. They do not converge over there poles. Did their chance of collisions change?

[russdill]

First, neither satellite had a 90 degree inclination. Second, it doesn't matter if they did. The number of collisions possible wouldn't change.