Well not really Scabs as there wasn't a picket line that we know of.
I watched ESB last night and caught a bit of dialog that has escaped me before. When Han and crew first get to Cloud City Lando explains that they are small enough not to get noticed by the Empire and that they aren't a member of the Miners Guild as they are small enough to not be noticed by them either. As he puts it, "It has it's advantages".
Sounds like Lando likes his workers to be non-Union which permits him to operate without the confines of employee workgroup contracts. Perhaps this led to the Empire being able to walk right in and give Lando an offer he couldn't refuse. With an employee group that wasn't very unified and trying to operate without Guild influence they were quick to adopt what ever offer the Empire gave them in an attempt to keep some sort of Quality of Life. Then when the deal changed they had little recourse and had to take what was given. If they didn't they would be getting a lot more attention from the Empire as well as new attention from the Miner's Guild.
When I heard Lando's comments it put a lot of what happens on Cloud City into perspective. A lot of familiarities between what unfolds there and what we see in Union/non-Union labor disputes.