I believe there will be many lines of defense:
All space debris of significant size (like single screw) is tracked now. It'll get more expensive, so NASA or whatever agency will replace it will have to charge for access to their data. Cheap captains/companies may try to buy one set a year, or after each significant battle, and compute everything on their own in the meantime. Big companies will probably have a daily subscription with emergency updates. First thing? Do not be where the debris is.
A ticket for littering
No joke here. Anyone caught at littering will be fined by Earth or Mars government. Intentional creation of debris will send someone bankrupt in no time. "Space Police" would track vessels involved in littering. Will know where they landed. If space station refuse to arrest such vessel will be fined, or put on serious embargo to make it not useful and it's inhabitants' lives miserable.
Cleanup by agencies
e.Deorbit is planned for 2021. Other agencies has their plans, too. financing? Of course taxpayers, launchpad fees. In other words, nothing new here. Well, maybe except space littering tickets, these should be use to pay for removal.
There is no stealth in space. And debris do not try to hide at all.
Imaging Radar Alone, or jointly with the Max-Planck-Institute of Radio Astronomy’s 100 m telescope at Effelsberg in Germany (bi-static mode), snapshots typically of 24 hours duration can be taken of the current space-debris population to provide statistical information and rough orbit parameters for objects as small as 1 cm at altitude up to 1000 km.
Creating Beam Park In this operating mode, the radar beam is maintained in a fixed direction with respect to the Earth and all objects that pass through the beam are registered. In the course of one day, the Earth’s rotation scans the beam through 360 deg in inertial space. From the backscattering of the radar signal, the size of the object and some of its orbital parameters can be determined. The FGAN radar is sensitive enough to detect 2 cm sized objects at a distance of 1000 km. This primarily statistical information on the small-size terrestrial debris population in the LEO (Low Earth Orbit) region can be used to validate space-debris models.
You want both 1cm minimal size of an object. And you want as long distance as possible. What you do not want is 100m telescope or having only statistical information. But improvements can be made, especially when you do not have any atmosphere to overcome.
Again, as in first line, once you know it's there, you can adjust your trajectory to avoid it.
Objects under certain size are effectively harmless, because you want to be safe from micrometeorites anyway and spaceships are built to withstand micrometeorite hit. Heat one point of debris enough to turn it into gas, and you'll change it's trajectory. Hopefully in a way that will make it miss you. And if you break it in half in the process? Hey, it's twice the tracking, but half the momentum! So chances next vessel will survive hit by one of the parts are somehow increased.
Probably, captain could also claim a small reward if he could prove he used it in a Laser Broom way, deorbiting some debris.