There's a belief that the term scab, referring to a non-union worker who crosses a picket line, was called such because it's an acronym meaning, variously, "Still Collecting All Benefits" or "Still Can Afford Beer".

This is not the case. Calling a non-unionized strike breaker a scab goes back to the 19th century. Initially scabs were workers who simply refused to join a union and they were considered despicable people. For about 300 years previous, scab simply referred to a despicable person. As labor laws changed, allowing unions to force out all non unionized workers for a given trade, scab came to refer to only non-unionized replacement workers brought in during a strike.

It's interesting to note that the scab (as in the original meaning... a crust that forms over a wound) goes back to the Old English term for scab which was sceabb . Some pronunciations of sceabb sounded like "shab". From this the modern English term "shabby" was derived.