[Dylan16807]

Whatever you do to launch an object higher, it will return to its original altitude once per orbit. If you want to stay high you first have to boost up and then you have to boost again half an hour later, which will happen just about never with debris.

[lxgr]

You'd still have an eccentric orbit intersecting some "higher" ones periodically, no?

Certainly less dangerous than something "going the wrong way" in a given orbital shell, but not sure if it's completely negligible either.

[Dylan16807]

For the lucky few pieces that launch at just the right angle, they'll spend a few months or years intermittently intersecting higher orbits.

But almost all the debris will either stay close to the original orbit or burn up within hours.