Fugitive Slave Act of 1850:
Any person aiding a runaway slave by providing food or shelter was subject to six months’ imprisonment and a $1,000 fine.
Slave catchers often acted without restraint much the same as today’s bounty hunters. There was violence.
Again, why would you want to be a member of that club? At some point don't you think someone should have said "Get them out of the Union!"