<-- Spoiler Warning -->
District 9 presents libertarians with challenging situations where thorough going libertarianism does not seem plausible. Let us see what some of the major difficulties are.
1. Wikus remarked briefly in the movie that prawns do not grasp the concept of private property well. Right to private property is one of the central right humans posess and it is known to us by common sense. My laptop that I use to type up this piece is mine, not yours, since I purchased the right to ownership of laptop with money. The money in turn was earned justly through my labour. So if prawns cannot even respect one of the most fundamental rights humans have to create a civil society, how can prawns and humans coexist?
2. Prawns are sufficiently intelligent and communicable unlike other animals. Therefore making contracts between prawns and humans are possible. But prawns also show very little restraint in their action and act violently against others when their needs are not met. This makes making contract with prawns to be difficult. Even when the contracts are made, people expect the contract to be broken easily.
3. Prawns are invasive and violent. They are very likely to ignore the rights of humans, so keeping the rule of "innocent proven guilty" is difficult.