Klaus stopped the ship when they were just 10,000 miles away from planet Korvel-3. That is a safe enough distance to observe the planet that has been taken over by bandits.
Of course, not all of the planet is infested by bandits, but since Korvel-3 is a mining planet, the moment their mine was taken over, the entire planet could be considered a hostage.
So, entering anyhow is just too dangerous, considering he would be dealing with immortal stage bandits. They are dangerous and unpredictable. So while Klaus may be able to brazenly enter, he wouldn't put the lives of the hostages in danger.
Of course, with the cloaking tech of the S-class ship he is using, he could enter without anyone reading him. However, that is a maybe, and Klaus isn't about to take that gamble.
The lives of the hostages are too important to gamble with.
