A remark about borderline cases of scabbing.
Borderline cases are important and interesting. (1) They test the limits of our moral views, and force us to clarify exactly what those views are. (2) They reveal that, sometimes, easy answers are not so easy. (3) Sometimes a person finds herself having to deal with a borderline case in real life. The first borderline case brought up in this discussion was Unionist's example, " if you volunteered to take your neighbour's garbage as well (whether paid or unpaid), then I think we might be approaching "scab" territory." And the language Unionist used -- "might be approaching" -- evinces the tentativeness that is appropriate in borderline cases.
Snert's example of looking after a neighbour's child and Ghislaine's example of dealing with trash of a neighbour with mobility issues are also reasonable and interesting examples. I would say this: in borderline cases, even if the action is scabbing, that consideration might be trumped by other equally weighty considerations -- having to do with your neighbours' health or with the safety of their children. We could all imagine cases in which the only way to save a dying child (a trite example, I know) would be to engage in an action that would otherwise be reprehensible. When moral considerations collide like this, a person has to make a judgement call of course, and make a decision (i.e., either to take the neighbour's trash or not to). But, even when one disagrees with someone else's judgement call, I think that one should recognize the difficult mix of moral considerations that might be at stake.