In this context (ie subletting against the terms of the agreement), I'd say it's a direct interference with the property rights of the owner, which to me is a p

In this context (ie subletting against the terms of the agreement), I'd say it's a direct interference with the property rights of the owner, which to me is a problem, although I accept others might take a different view on that. But it also often comes with all the usual issues with gray markets - subtenants might in practice have very few enforceable rights, tax evasion can be common, etc etc.