The Mercenary companies have built a code of conduct to help insure a long and lasting life for the company. These rules of Conduct are generally enforced unless the payer of the mercenary company decides that the rules are unacceptable. In that case the cost of doing business for the buyer goes up.
1. The first code is that of giving quarter when quarter is asked for. War is a serious business and dead soldiers are hard to replace, especially experienced ones.
2. Mercs can be ransomed back to their original companies at generally a fixed rate depending on their level of competence. If the original company fails to provide a ransom, the merc can be hired by the company to repay the ransom debt. The merc has two choices, join or be let go sans all his equipment.
3. The merc is allowed to retain his equipment unless the ransom fails.
4. Civilians are not to be harmed unless they take up arms or the hirer wishes to make examples of the civilian population. If the hirer wants to make examples of the civilian population, this generally requires additional recompense on the part of the hirer.
Companies that fail to honor these agreements tend to be treated harshly in future combats.
This would be mitigated if the employer wishes to have the company not comply with the code of conduct.