EDIT: This is simply my view so I should probably start this off by saying it is IMTU.
Whenever people start talking about bounty hunters I feel the need to point out that traveling round trip to follow and track down someone and then return with them is not cheap. Also take into consideration that only sometimes is the bounty hunter successful so the successful bounties need to pay for all the expenses of "getting their man" and cover the cost of some failed attempts too.
To me, it's more likely bounty hunters don't go jumping around and just study all the "wanted posters" and hang out at their local star port looking for any matches.
Some star ports will have facial recognition and other means for checking anybody coming and going against the latest database of wanted people.
Some societies may feel that if the criminal has fled it is no longer their problem. Make sure they don't come back. Report them to the Imperium so that they can be "flagged". But it's not worth the cost to imprison them let alone extradite them or pay rewards/bounties.
Sometimes a criminals crime is not sufficient to be extradited back to the system where the crime was committed or be prosecuted by the Imperium. Some local crimes are completely ignored by the Imperium - like parking tickets, littering, or wearing red on a religious holiday. Certain crimes will get you "flagged" as a suspected criminal. "Suspected of assault and hovercraft theft on Efate." "Suspected of rape on Pixie." Being flagged is serious enough that major liners wont give these suspected criminals passage (#1). A criminal might find that they have become persona non gratis and many systems won't "stamp their passport" and let them pass through customs (#2). They may find themselves stuck in the star port like Tom Hanks in "The Terminal".
Maybe the criminal got to whatever new system before word of their deeds catches up to them. Perhaps they'd live pretty good in a low tech system or low law system, if that's the type of place they want to spend the rest of their life. In other systems word would eventually get out and while they might not extradite you or imprison you for crimes allegedly committed elsewhere it could have a variety of consequences like not being able to get credit, own real estate, get a job, and so on. "I'm sorry sir, but until you get this outstanding charge dropped..."
(#1) Insert adventure when a small tramp freighter is having trouble filling the staterooms and is short on credits.
(#2) Insert adventure when a tramp freighter is hired to smuggle someone down to the planet without going through customs.