Clarification edit: Coercion in response to coercion is self-defense. If someone physically forced their way to your property, you have a right to defend yourself, and this should be enforced. We need some way make sure there's no coercion in the market.
I know because I lived through it. Games before steam and client-server based rpg's that were designed to trick gullible consumers to give up PC game ownership.
Many (most?) hardcore libertarians actually oppose intellectual property, because it's not justified under the reasoning used to justify normal property. If someone puts a gun to your head and steals your car, they're clearly using violence to force you to do something you don't want to do (give them your car). If someone downloads a copy of a game you published and shares it with their friends, they're not doing any violence against you or making you do something you don't want to do. They may be making it less likely for other people to pay you money for that game, but under that minimalistic libertarian framework nobody has the obligation to pay you for a game just because you made it.
I also know of some libertarians that do not oppose IP itself, but claim that any system to enforce (and definitely our current patents system) is worse than no system at all.
Otherwise if you want a house all you have to do is go bankrupt then pick an empty mansion.
But that would require coercion, since that person doesn't want to leave.
After all, if the person squatting on what you consider to be your property doesn't recognize your claim of ownership, it would seem that you pose a greater threat to them than they do to you, especially if you're trying to remove them from the property when they're not presenting an immediate threat of physical harm.
Just curious, have you ever been in a fight or had a gun pointed at you?
Are you seriously arguing for an economy where anyone can build a skyscraper out of any material?