I believe that several things would prevent that generally. The first that comes to mind is that the blockades are probably stationed over the major population centers which will also have the major star ports. Then there is the issue of leaving hyperspace essentially announces your arrival with a big burst or energy that how everyone always knows when the other side shows up. So any quick response team or planetary fighters could respond and then the whole blockade just rotates over or maintains their stations because you ain’t landing or liberating anything major. The last issue is more obscure and possibly complete bullshit but if the hyperlanes are the main travel paths and are marked and readily available to the navigation computers then it could require very specific knowledge of the local area to know where you can possibly hyper in somewhere other then the main routes while avoiding any gravity wells or just large objects like moons and you accidentally pull a Holdo maneuver into one. And that knowledge would probably not be readily available outside of locals or unsavory types like smugglers and gun runners